1. IntroductionWelcome| 00:04 | With digital cameras, it's easy to
get hung up on the idea that megapixels
| | 00:08 | equals image quality.
| | 00:10 | And sure you need a certain pixel count
to go to a reasonable amount of detail.
| | 00:14 | But on today's cameras with their
huge quantities of pixels, the caliber of
| | 00:18 | the lens you have has as much to do with image
quality as the number of pixels that you have.
| | 00:23 | The lens you choose determines
everything, from the field of view and
| | 00:27 | magnification in your shot, to how
sharply focused it can be, to how faster
| | 00:31 | shutter speed you can use, and how
shallow your depth of field can be.
| | 00:34 | In other words another words
understanding your lens is critical to taking good photos,
| | 00:38 | and that's why we've
dedicated an entire course to lenses.
| | 00:42 | Our study begins with focal length,
wherein you will see that while your zoom
| | 00:47 | lens may be a great convenience,
| | 00:49 | it's also an easy way to dramatically
alter an image without even realizing it.
| | 00:53 | From there, we'll move on to choosing a lens.
| | 00:55 | We will study some advanced auto-focus concepts.
| | 00:58 | We will explore the vagaries of
telephoto and wide-angle lenses.
| | 01:01 | Look at filters. Or look through filters.
| | 01:04 | And finally, we'll talk about maintenance.
| | 01:06 | Again, while this may seem
like a gear-centric course,
| | 01:09 | remember that photography is
an inherently technical medium.
| | 01:12 | To achieve your artistic ends, you
have to understand your gear and the craft
| | 01:16 | that is required to use it well.
| | 01:17 | We will be studying both the art
and craft of photography throughout this course.
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| Who is this course for?| 00:01 | The title lenses might make you think
that this course is going to be about
| | 00:04 | technical optics stuff and lens buying.
| | 00:07 | And while there will be some technical
discussion, this course is not meant as
| | 00:11 | a lesson in optics.
| | 00:13 | Several of your camera's most
critical controls sit on the lens.
| | 00:17 | Your choice of lens and how you use it
will determine the composition of your shot,
| | 00:21 | set the sense of space and
proportion in the final image,
| | 00:24 | how deep or shallow the depth of
field in your image will be, and overall
| | 00:28 | sharpness and contrast.
| | 00:29 | Furthermore, your choice of lens and
your understanding of its controls will
| | 00:33 | determine whether you can work as quickly
as you need to get the shots that you want.
| | 00:38 | This course is going to assume a
fundamental understanding of exposure, so if
| | 00:41 | you haven't yet worked through the
Foundations of Photography: Exposure course,
| | 00:46 | you might want to do that
before taking on this one.
| | 00:48 | I'll be using terminology here that
is defined and explained in exposure as
| | 00:52 | well as building on some of the practices and
habits that you should have developed there.
| | 00:56 | This course will be useful no matter
what type of camera you have, be it a
| | 00:59 | high-end SLR or a tiny point-and-shoot.
| | 01:02 | All lenses have the same properties,
even though they might have very
| | 01:05 | different characteristics.
| | 01:07 | Finally, I'm a strong believer
that it's practice that makes a good
| | 01:10 | photographer more than any gear choice,
and that's in spite of this incredible
| | 01:15 | collection of lenses I have sitting
here and more than any postproduction
| | 01:18 | effect you might use.
| | 01:20 | So, along the way, be sure to
experiment with the ideas that we are offering,
| | 01:24 | and try some of what you see here on your own.
| | 01:26 | You can do most of these things around
the house if you like, but to get the
| | 01:29 | most out of this course, you are
going to need to get out of your chair and
| | 01:32 | grab your camera.
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| Why does the lens matter?| 00:01 | Camera vendors are quick to extol
the huge pixel counts in their cameras.
| | 00:05 | Sometimes it's even written on
the front of the camera itself--
| | 00:07 | that's that megapixel number.
| | 00:09 | And certainly pixel count is
important, especially if you like printing big
| | 00:12 | images, but sometimes it's
also a bit of a marketing ploy.
| | 00:16 | It's a single number that a vendor
can use to represent overall quality.
| | 00:20 | This camera has 14 megapixels
therefore it must be better than this one that
| | 00:23 | only has 10, that sort of thing.
| | 00:26 | There are a lot of factors that
contribute to the overall image quality that
| | 00:29 | your camera produces.
| | 00:31 | A very significant one is image
processing that happens inside the camera itself
| | 00:35 | and a camera that does a better job of
interpreting the data that it collects
| | 00:38 | will yield images with less noise,
better color, and possibly better sharpness no
| | 00:43 | matter how many pixels
it may have on its sensor.
| | 00:46 | But regardless of your camera's
pixel count and no matter how great its
| | 00:49 | image processing is, if you stick a
lousy lens on that camera, you will get
| | 00:53 | compromised images.
| | 00:55 | I often hear people say, "Oh I am
going to get that new cell phone with a
| | 00:57 | five megapixel camera, because then I won't
have to carry around my real camera anymore."
| | 01:02 | There are some cell phones today
that can take very good images but with
| | 01:05 | current technology, there is no way
that a tiny cell phone lens can compare to
| | 01:10 | the lens on even a point-and-shoot
digital camera, even if the point-and-shoot
| | 01:14 | has a lower pixel count.
| | 01:15 | Unless you're specifically going for a
grungy toy camera look, a quality lens is
| | 01:21 | a must if you want images
of high technical quality.
| | 01:23 | I say technical quality, because you can
take a compelling image with any camera
| | 01:28 | and lens, but if you want to improve your
chances of getting good sharpness, good
| | 01:32 | contrast and good color
then you want a good lens.
| | 01:36 | Different lenses also impact your
creative choices, possibly giving you
| | 01:39 | more artistic control.
| | 01:41 | For example, the focal length of your
lens has a large bearing on the types of
| | 01:45 | subjects that you can shoot
and how you might shoot them.
| | 01:48 | This image, for example, lends itself
to wide-angle shooting, which means you
| | 01:52 | want a lens with a short focal length.
| | 01:54 | The ability to shoot with deeper or
shallower depth of field also gives you
| | 01:58 | tremendous creative flexibility.
| | 01:59 | So for example, you might find that for
the types of shots you like to take,
| | 02:03 | a ery fast prime lens with an
extremely wide aperture is a better choice for
| | 02:08 | you than one with a slower lens,
because you'll be able to shoot with
| | 02:10 | shallower depth of field.
| | 02:12 | Finally, sometimes a lens just has an
ineffable, un-definable quality about it.
| | 02:17 | A particular way that it handles contrast.
Maybe there's just something about it
| | 02:21 | that you really like and so
you learn to exploit that.
| | 02:24 | You don't have to have a great lens to
shoot great images, but it sure helps.
| | 02:28 | What you do need is the understanding
of how to take advantage of your lens and
| | 02:32 | that understanding begins with focal length.
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| Changing lenses| 00:00 | One of the great advantages of an SLR
is that you can change the lens.
| | 00:04 | This affords you a tremendous level of
creative and technical flexibility.
| | 00:08 | You can choose lenses that offer
different fields of view, more or less
| | 00:12 | magnification, better image quality, the
ability to shoot at lower light, and on and on and on.
| | 00:17 | Changing lens is fairly simple but
there are a couple of things that you
| | 00:20 | should keep in mind.
| | 00:21 | First, you don't want to drop
anything and so I am going to show you some
| | 00:25 | techniques to try and help
you keep from doing that.
| | 00:27 | Second, you want to move kind of
quickly, because once you take the lens off,
| | 00:30 | the image sensor in your camera
is exposed and you don't want dust and
| | 00:34 | stuff getting on there.
| | 00:35 | So, here's a Canon SLR.
| | 00:37 | All SLRs are going to have a lens
release button on them of some kind.
| | 00:42 | You can press and hold that
while you twist the lens off.
| | 00:44 | Before I do that though, I want to put
my lens cap on, because as I take the
| | 00:48 | lens off, I am going to be handling it.
| | 00:49 | Odds are I am not going to scratch or
break anything but I just don't want
| | 00:53 | fingerprints on there or anything like that.
| | 00:54 | So I am putting a lens cap on.
| | 00:57 | Now, I will find myself changing
lenses in a couple different ways.
| | 01:00 | Sometimes I hold the camera with my
left hand, so that I can press and hold the
| | 01:04 | button here and then I can twist
with my right hand and pull it off.
| | 01:08 | At other times, I'll hold the camera
like this and then with one hand I can come
| | 01:13 | in here and mash the button
and twist, and take the lens off.
| | 01:17 | So, once I get my lens off,
I need somewhere to put it.
| | 01:20 | It's great right here because I have
got this table, but you don't always carry
| | 01:23 | a table around with you.
| | 01:24 | So, what I tend to do is put in the crook of
my arm and make sure it's good and secure there.
| | 01:28 | Then I grab my other lens.
| | 01:31 | Your lens has a body cap on it or a cap
on the body end of the lens, that needs
| | 01:35 | to come off and you got to
have somewhere to put that.
| | 01:38 | You can stick in your mouth.
| | 01:39 | you can carry a table
around with you and set it there.
| | 01:41 | I am going to put it right here for now.
| | 01:43 | There's a red dot on here.
| | 01:45 | It lines up with a red dot on
here and then I just twist.
| | 01:49 | Nikon lenses twist the other
direction to get them on and off.
| | 01:52 | It's easy enough to figure out.
| | 01:53 | If you twist in one direction and it doesn't
go, you are twisting in the wrong direction.
| | 01:56 | So, now I have got this body cap.
| | 01:58 | What do I do with it?
| | 01:59 | Right, I have got this
lens in my armpit right now.
| | 02:02 | I will put the body cap on my
there and now I have changed lenses.
| | 02:05 | So, like I said, you want to do that
kind of quickly and the reason is when I
| | 02:09 | take the lens off, you can see right
in there is the mire. That's the reflex
| | 02:14 | mirror that makes my viewfinder work
and behind that is the image sensor.
| | 02:19 | Now, you don't have to just be panicked,
because thinking at the moment you
| | 02:23 | take lens off the sensor is
going to fill up with dust.
| | 02:25 | It's not that bad but you do want to be careful.
| | 02:27 | And some things you can do, just to
minimize the risk of sensor dust is make
| | 02:31 | sure when you take the lens off, keep the
camera pointed down while you do the other work.
| | 02:36 | If you are standing somewhere really,
really windy, may you want to think about
| | 02:40 | not changing lenses. You probably don't
want to just sit around talking, waving the
| | 02:43 | lens and the camera around,
like I am doing right now.
| | 02:46 | Most importantly though the main way
that sensor dust gets to your sensor is
| | 02:50 | through the end of the lens.
| | 02:52 | So, be sure you always keep
the body caps on your lenses.
| | 02:55 | And when you're not using a body cap
from the lens, don't put it in your pocket.
| | 02:59 | Put it on other lens, because otherwise
all you're doing is taking lint and dust
| | 03:03 | from your pocket and transferring it
directly to the lens and from there it
| | 03:07 | gets into the camera.
| | 03:09 | So, changing lenses is something you
want to kind of be able to do with your
| | 03:12 | eyes closed, because you need to
be able to do it quickly sometimes.
| | 03:16 | One thing that you might consider
as you get more serious is a lot of
| | 03:19 | photographers carry more than one camera body.
That keeps them from having to change lenses.
| | 03:23 | If you tend to shoot things where you
want access to different lenses very
| | 03:27 | quickly, maybe a telephoto lens and a
normal or wide-angle lens, carry two
| | 03:31 | cameras with a lens on each one then you
are not having to change lenses at all.
| | 03:35 | So, do a little practice with your lens changes.
| | 03:37 | Get where you can do them comfortably
without dropping anything and without
| | 03:40 | exposing your sensor for too long.
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| A word about camera brands| 00:01 | If you've been shopping for a camera,
you already know that there are a lot of
| | 00:03 | different brands and a lot of
different cameras out there.
| | 00:06 | For that reason, we have made this
course camera independent or camera agnostic.
| | 00:11 | There is no way that we can cover
the specific controls of even one
| | 00:14 | brand's worth of camera.
| | 00:16 | And the good news is there's no
reason for us to, because the things you are
| | 00:19 | going to learn here apply to any
camera no matter who makes it and what
| | 00:23 | technology it may have inside. Because
a lot of what we are going to talk here
| | 00:26 | is really just about physics
and the way that light works.
| | 00:30 | That said, I want to say that you are
going to see a lot of Canon gear here.
| | 00:35 | Canon makes great cameras. So does
Nikon, so does Pentax and so do Sony and
| | 00:40 | Panasonic and Olympus and
Casio and many, many others.
| | 00:44 | The reason that we have chosen Canon
for this course is that we have some
| | 00:47 | particular technical needs for some of the
things that we are going to do in our production.
| | 00:51 | You're going to see large displays of the live
view feed from a camera and some other things.
| | 00:57 | And at the time of the shooting,
we need Canon cameras to do that.
| | 01:01 | Over the years, as a working
photographer, I've shot with many different brands
| | 01:04 | of cameras and over the years as a
journalist I've gotten to review and
| | 01:08 | evaluate even more cameras than that.
| | 01:10 | And I can tell you that right now,
the digital camera market is completely mature.
| | 01:15 | For the most part, if you go and buy
a camera from one of the big camera
| | 01:18 | vendors, you're going to
get a great photography tool.
| | 01:22 | There's no need to get hung up, there
"is there a better camera that I could have gotten"
| | 01:26 | or "if I had this camera, I
would be a better photographer."
| | 01:29 | It's the photographer that makes
a good picture, not the camera.
| | 01:32 | So though you're going to see all
these camera Canon gear and though we like
| | 01:36 | all of this Canon gear, that's not that
we're advocating that Canon is the best
| | 01:40 | thing to go and buy.
| | 01:40 | What matters is what you do with the camera.
| | 01:42 | It's up to you to pick the camera that
has the features that you think you need
| | 01:46 | and an interface that makes sense to
you and that delivers a level of quality
| | 01:49 | that's right for the type
of shooting that you do.
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|
|
2. What Is a Lens?What is a lens?| 00:01 | We all know the law.
| | 00:03 | Einstein's spelled it out for us.
| | 00:04 | Nothing is allowed to travel faster than light.
| | 00:07 | And yet every day you
manipulate the speed of light.
| | 00:10 | Every time you use a lens, even the
lenses in your eyes, you slow down light.
| | 00:15 | Because lenses work by refracting, bending and
slowing light to target it onto a particular area.
| | 00:21 | In the case of your eye, your eye's lens tries
to target light onto the back of your eyeball.
| | 00:26 | In the case of your camera, your
camera's lens tries to target light onto the
| | 00:30 | focal plane, where a piece of
film or a digital image sensor sits.
| | 00:35 | If the lens aims short of the target
or goes past the target, then the image
| | 00:38 | will be out of focus, and if the lens
can't focus all wavelengths of light to
| | 00:43 | the same point, remember white light is
composed of all other colors of light,
| | 00:46 | then you may end up with colored
fringes around some areas in your photo.
| | 00:50 | At the simplest level a lens
is just a curved piece of glass.
| | 00:53 | When it's curved on both sides like this
magnifying glass, the light goes in one
| | 00:58 | side, gets bent and slowed, and
comes out the other side a little larger,
| | 01:02 | meaning that what you're
looking at appears bigger.
| | 01:04 | Other types of lenses might be
curved on one side and flat on the other.
| | 01:08 | Some are curved inward, those are concave,
while others are curved outward. Those are convex.
| | 01:13 | Eye glasses though, or a magnifying glass,
use a single lens, one piece of glass.
| | 01:18 | Things get far more interesting
when you start combining lenses.
| | 01:22 | On October 2, 1608, Hans Lippershey from
the Flemish province of Zealand applied
| | 01:28 | to the Hague for a patent on a certain
instrument for seeing far, and soon after
| | 01:33 | that there were gobs of
people making spyglasses.
| | 01:37 | A typical spyglass has a weak
convex lens at the far end and a strong
| | 01:42 | concave lens near the eye, and these devices
were constructed largely by trial and error.
| | 01:48 | It was Galileo who worked out the math
behind the optics of multiple lenses,
| | 01:52 | improved the simple
spyglass to a practical telescope.
| | 01:55 | Now, similarly your camera lens
is not a single piece of glass.
| | 02:01 | Instead it's a lots of lenses, lots of
pieces of glass, sometimes a dozen or more.
| | 02:05 | Each individual lens is called an element.
| | 02:08 | Each element serves a particular
optical function and sometimes elements are
| | 02:12 | cemented together into
groups throughout the lens.
| | 02:16 | A group serves a single optical function.
| | 02:19 | Lens design is a process of trade-off
and balance, so for example, you might set
| | 02:23 | out to design a lens with a particular
magnification power and so you choose
| | 02:27 | some elements that give you
that amount of magnification.
| | 02:29 | But maybe those elements yield
an image with bad distortion.
| | 02:32 | That is, lines on the edges of the frame
are bent and curved, so you add another
| | 02:37 | element behind that to correct the
distortion, but then maybe that element
| | 02:40 | introduces a bad lens flare, a bright
reflection that washes out part of the
| | 02:43 | image, so you add another element
to correct that and so on and so on.
| | 02:47 | When you are lens shopping, you might
see that a particular lens has 12 elements
| | 02:51 | arranged in three groups or something like that.
| | 02:54 | If a salesman offers that to you as a
selling point, you should definitely give
| | 02:57 | a knowing nod indicate that you've
already worked out the math of the optics in
| | 03:01 | your head and that you deeply
understand the advantage of this construction.
| | 03:04 | But in the end a number of elements in
group should not be a buying concern,
| | 03:08 | unless you're an optics nerd who has
the technical curiosity to satisfy.
| | 03:12 | Later we're going to look at how to
choose a lens and internal construction is
| | 03:16 | not going to be one of our big concerns,
what does matter in your use of a lens
| | 03:21 | is an understanding of focal length,
aperture, and focus and we're going to
| | 03:24 | study all of those in the course.
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| Field of view| 00:01 | Your eye has a particular field of view. That is,
| | 00:04 | you can see a particular
amount of width with a naked eye.
| | 00:07 | It's a little hard to qualify
exactly what normal human field of view is,
| | 00:12 | because our peripheral vision is very
wide, but that gets very unfocused at the edges,
| | 00:17 | so usable field of view
is a difficult thing to gauge.
| | 00:20 | Things outside of my field of view I can't see.
| | 00:23 | A lens also has a field of view which is
determined by the lense's focal length.
| | 00:28 | Technically focal length is measured in
millimeters from the middle of lens to
| | 00:33 | the principal point of focus of the lens.
| | 00:35 | Now you don't actually need to know
where these points are. All you have to know
| | 00:39 | is what happens when you change focal
length and we will be looking into that
| | 00:42 | extensively later in this course.
| | 00:45 | Any lens that offers the same field of
view as the human eye is said to be a
| | 00:49 | normal lens. Here's an image shot
with a normal lens and it looks pretty
| | 00:53 | much like the field of view that
you would expect to see if you were
| | 00:56 | standing in this location.
| | 00:58 | Again if you were actually there,
you would have a larger peripheral sense but
| | 01:01 | that part of your field of
view would be very out of focus.
| | 01:04 | Any lens that is longer than normal is
considered a telephoto lens. As you go
| | 01:10 | more telephoto your field of view gets
narrower and magnification increases.
| | 01:15 | Things that are farther away appear closer.
| | 01:17 | Any lens that is shorter than normal is
considered a wide angle lens. Your field
| | 01:22 | of view gets really wide, which means
you can take in a wider vista, but most
| | 01:26 | things in your shots appear
small because of this wider angle.
| | 01:29 | So your first important field of view
concept is this: as focal length increases,
| | 01:35 | field of view narrows and
magnification increases.
| | 01:40 | Trust me you know all this stuff already.
When you zoom in things get bigger and
| | 01:44 | appear closer. What you may never have
thought of before is that this zooming
| | 01:47 | function results in lessening of field
of view. When you zoom out, things get
| | 01:52 | small and you have this
nice big wide field of view.
| | 01:55 | Now it might seem like we're just
hassling with putting words on things that
| | 02:00 | you can intuit and feel your way
through, but it's very important that we had
| | 02:03 | this terminology worked out for most of
what's going to follow in this course.
| | 02:07 | So for example, when I say, "Go shoot
with a telephoto focal length," you now
| | 02:11 | know that I mean a focal length that's
longer than a normal lens. When I say,
| | 02:16 | "Interiors are best shot with a wide
field of view," then you know that I mean a
| | 02:21 | shorter focal length.
| | 02:23 | So you want to know what focal
length is normal for your camera, what is
| | 02:27 | telephoto and what is wide-angle.
But what is a normal focal length?
| | 02:32 | That depends on your camera's image sensor.
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| Image sensors and field of view| 00:01 | A lens is a cylinder. It's round.
| | 00:06 | There's a lot of complicated topics in
photography so I thought would really revel in
| | 00:09 | this simple one for a moment.
| | 00:10 | Anyway light comes in the front of your lens.
| | 00:13 | It gets focused by the lens
and is projected out the back.
| | 00:16 | Thanks to the physics of optics,
the image gets flipped upside down in
| | 00:19 | that process, but because your lens is round
it projects a round image out its backside.
| | 00:25 | The sensor in your camera though is
rectangular, so it crops a rectangular image
| | 00:30 | from that circle that your lens projects.
| | 00:32 | Now think about what happens if you
change the size of that rectangle.
| | 00:36 | A smaller rectangle is going to crop
a narrower image, meaning one with a
| | 00:40 | narrower field of view.
| | 00:42 | In other words, the same focal length
will deliver a different field of view
| | 00:47 | depending on the size of the image
sensor in your camera. Because that image
| | 00:51 | sensor is going to crop a
narrower or wider part of the image.
| | 00:55 | Earlier we explained that a lens with
the same field of view as the human eye
| | 00:59 | is considered a normal lens.
| | 01:01 | However as you have just seen,
because sensor size matters, there is no
| | 01:04 | universal focal length that
yields a normal field of view.
| | 01:08 | Normal varies depending on the size
of the image sensor in your camera.
| | 01:13 | So to calculate what is normal for your
image, you're going have to do a little math.
| | 01:18 | It's easy math though. Just simple arithmetic.
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| Focal length multipliers| 00:01 | For more than 70 years, 35mm film was
the dominant photographic medium.
| | 00:06 | Then digital photography came along.
| | 00:08 | 35mm film is still used for some still
photography and used a lot for motion
| | 00:11 | picture photography.
| | 00:13 | Like a digital sensor, a piece of 35mm
film crops a specific sized rectangular
| | 00:18 | image out of the image
circle projected by a lens.
| | 00:21 | After 70 years of using 35mm film
people got used to specific focal lengths
| | 00:26 | having specific fields of view.
| | 00:28 | So photographers became accustomed to
the idea that a 50mm lens was a normal lens,
| | 00:33 | because when used with 35mm film a
50mm lens has roughly the same field of
| | 00:39 | view as the human eye.
| | 00:40 | Anything longer than 50mm is
telephoto. Anything shorter is wide-angle.
| | 00:45 | With 35mm film a 28mm lens is pretty wide.
| | 00:49 | A 16 or 24 millimeter lens is ultra-wide.
| | 00:53 | Conversely, 300mm has a good amount of
telephoto power and 600mm puts you in the
| | 00:58 | realm of serious surveillance.
| | 01:00 | Most digital cameras had image sensors
that are smaller than a piece of 35mm film.
| | 01:05 | That means they crop a narrower
rectangle from the circle projected by the lens.
| | 01:09 | So if you take the 50mm lens from your
35mm camera, which yields a normal field
| | 01:15 | of view, and put it on a digital camera
which has a smaller sensor, you're going
| | 01:20 | to get an image with a narrower field of view.
| | 01:22 | Let's look at a specific example.
| | 01:24 | This is a Canon 7D.
| | 01:27 | It has an image sensor that's the size
of a piece of APS film. That's a little
| | 01:31 | smaller than 35mm film.
| | 01:33 | The Canon Rebels and 10 series
cameras also use the same size sensor.
| | 01:38 | With this sensor, any lens that I put
on the camera has a 1.6x crop factor
| | 01:43 | for its field of view.
| | 01:44 | So if I put this 50mm lens on this
camera, which is a normal lens on a 35mm film
| | 01:51 | camera, I end up with an equivalent
field of view of 80mm, or 50 times 1.6.
| | 01:59 | This means that the lens is
now more telephoto than normal.
| | 02:03 | 50mm and 35mm terms is normal.
80 is a little telephoto.
| | 02:08 | So after converting this to 35mm terms,
we realize that 80mm is no longer normal.
| | 02:14 | It is though a great portrait lens.
| | 02:17 | Many Nikon SLRs also use the sensor
that's smaller than a 35mm piece of film and they
| | 02:23 | have a multiplication factor of 1.5.
| | 02:26 | If your camera has a crop sensor, then
your manual should list the appropriate
| | 02:30 | multiplication factor.
| | 02:32 | If you tend to shoot with long lenses
then a crop sensor is great, because your
| | 02:35 | lens is end up with the field
of view of a much longer lens.
| | 02:38 | For example, if I put this big 800mm
lens on my 7D, I end up with an equivalent
| | 02:44 | field of view of 1280mm.
A tremendous amount of telephoto power.
| | 02:50 | The downside is if I want to shoot
wide-angle. Here is a 28mm lens which is a
| | 02:56 | nice wide-angle lens on a 35mm camera.
| | 02:59 | On my crop sensor 7D though we'll end up
having an equivalent field of view of a 44mm lens.
| | 03:05 | Means I've gone from wide-
angle to roughly normal.
| | 03:09 | Fortunately, as you'll see later most
vendors manufacture lenses specifically
| | 03:14 | designed for their crop sensor cameras.
| | 03:16 | Here is an Nikon D700 and a Canon 5D
Mark II. Both of these cameras have what are
| | 03:23 | called full-frame image sensors.
| | 03:25 | That is their sensors are the
same size as a piece of 35mm film.
| | 03:31 | With a full-frame camera
there is no multiplication factor.
| | 03:34 | So right now I've got a 24 to 70
millimeter lens on this camera and that's
| | 03:39 | equivalent to a 24 to 70 millimeter lens.
It's just like it would be on a 35mm camera.
| | 03:46 | This is a micro four thirds camera. We're
going to talking more about these later.
| | 03:50 | They're cool, in-between a
point-and-shoot camera and an SLR.
| | 03:54 | The sensor is bigger than what you'll
find in a typical point-and-shoot, but
| | 03:57 | it's smaller than either the APS sized
sensor and a crop sensor SLR and much
| | 04:02 | smaller than the full-frame
sensor and a full-frame SLR.
| | 04:05 | Micro four thirds cameras have
a multiplication factor of 2.
| | 04:08 | So right now I've got a 20mm lens on
here. That's going to make it equivalent to
| | 04:12 | a 40mm lens or roughly a normal lens.
| | 04:16 | I take it off though. It's one of the
beautiful things about micro four thirds
| | 04:20 | cameras is like an SLR they have
interchangeable lenses and I can put on this 14
| | 04:24 | to 42 millimeter lens.
| | 04:26 | 2x multiplication factor means this is
equivalent to a 28 to 84 millimeter lens.
| | 04:32 | It's a good walk-around range.
| | 04:35 | Here is a point-and-shoot camera kind of a
typical small little camera. This is a Canon S95.
| | 04:39 | I'm going to turn it on and
you'll see the lens come out.
| | 04:43 | So you can see physically
this is a very small lens.
| | 04:46 | The actual focal length of this
lens is 4.9mm, which is tiny, to 22 1/2
| | 04:52 | millimeters, but in 35mm equivalence,
because the image sensor in this camera
| | 04:57 | is so tiny, this lens has an equivalent
focal length range of 28 to a 105 millimeters.
| | 05:04 | Now you might be thinking, "I don't shoot
35mm film, I never have, so why should I care
| | 05:09 | what my digital camera is equivalent to?"
| | 05:12 | As you get more serious about
photography you'll probably get more cameras and
| | 05:16 | they might have different size sensors.
| | 05:18 | Having a single reference point for
what is normal, what is telephoto, what is
| | 05:22 | wide-angle can make it easier
to understand what you can expect from
| | 05:26 | different lenses on your different cameras.
| | 05:28 | And 35mm equivalency is the general
reference point that all manufacturers use.
| | 05:33 | So take a look at your lenses and your
camera manual and try to determine the
| | 05:38 | focal length equivalency of
your different cameras and lenses.
| | Collapse this transcript |
| Primes and zooms| 00:01 | Lenses come in two flavors: prime
lenses, which have a single fixed focal
| | 00:05 | length, that means they have one field
of view, and zoom lenses which have a
| | 00:09 | variable focal length.
| | 00:11 | So they have a field of view that
can go from wide to more narrow.
| | 00:14 | For the most part a lens with a longer focal
length will be physically longer. For example,
| | 00:19 | I've got this 400mm lens, which is as you
would expect much longer than this 50mm lens.
| | 00:26 | Now I say for the most part,
because zoom lenses can complicate things.
| | 00:30 | For example, I've got this 50mm lens
here and then I've got this is a 16 to
| | 00:34 | 35 millimeter zoom.
| | 00:36 | It's much longer than the 50. That's
because zoom lenses have complex mechanics
| | 00:41 | and sometimes require extra glass.
| | 00:42 | So even though this is
ultimately a shorter focal length, it's a
| | 00:45 | physically longer lens.
| | 00:47 | With primes you'll sometimes
find a kind of odd size variation.
| | 00:51 | For example, here is a 28mm lens and
here is a different 50mm lens. The 28mm is
| | 00:58 | a shorter focal length, but in this
case it's a physically larger lens.
| | 01:02 | That's because this lens can open to a wider aperture.
| | 01:05 | If the lens is really fast sometimes
it may require more glass and so it ends
| | 01:09 | up physically larger.
| | 01:11 | These days everyone is familiar with zoom
lenses, either from video cameras or still cameras.
| | 01:15 | Every point-and-shoot camera has a zoom
lens and of course it's not possible to
| | 01:19 | swap the lens on your point-and-
shoot camera for another zoom or prime.
| | 01:23 | The great thing about point-and-
shoots though is that their lenses are
| | 01:26 | physically very small and they
sit very, very close to the sensor.
| | 01:30 | As a lens gets shorter and narrower and
can be positioned closer to the sensor,
| | 01:34 | it becomes easier to engineer
a very good quality lens.
| | 01:37 | So even though this lenses tiny it
might actually deliver better quality than
| | 01:42 | some of these larger lenses for an SLR.
| | 01:44 | As you shoot more and as you practice
you're going to become more aware of what
| | 01:48 | focal lengths you tend to favor and how
picky you are about sharpness, flare, and
| | 01:52 | other potential lens problems. Right
now don't worry too much about whether the
| | 01:55 | lens you have is right for you. You'll
be able to make a more educated decision
| | 01:59 | in that regard as we learn more.
| | Collapse this transcript |
|
|
3. Focal Length, Camera Position, and CompositionFocal length, camera position, and composition| 00:01 | Zoom lenses are great for their
convenience. Rather than having to carry an
| | 00:04 | entire bag full of lenses,
| | 00:06 | I can just carry one lens and
have a huge range of focal lengths.
| | 00:08 | It makes my bag lighter.
| | 00:09 | It keeps me from having to swap
lenses all the time. That's all great.
| | 00:13 | Unfortunately, zoom lenses can also
make you lazy, because you might be walking
| | 00:16 | along and see a thing over there and go wow!
| | 00:18 | Look at that thing over there and
rather than having to think about where to
| | 00:21 | stand to shoot it, you just where you
are and you zoom in and you get the shot.
| | 00:24 | That might be the right shot, but
it's important to understand that
| | 00:28 | shooting something way over there
from over here is not necessarily the
| | 00:31 | same as going closer.
| | 00:33 | The image changes dramatically
depending on what focal length that I'm using.
| | 00:36 | Here is what I'm talking about.
| | 00:38 | Ben's standing over there, I'm standing over here.
| | 00:40 | I am going to take a picture of him.
| | 00:42 | To do that, I want to for this
particular picture I want to fill the frame with him.
| | 00:46 | To get that shot from way over here.
| | 00:47 | I've got to zoom in quite a bit. I'm at
about a 100mm here and there is my shot.
| | 00:54 | Reasonable enough picture.
| | 00:55 | He is filling most of the frame, but
watch what happens now if I go closer to him.
| | 01:01 | So I'm going to come up here now and
because I'm standing so much closer to him,
| | 01:05 | I need to zoom out.
| | 01:06 | So now I'm all the way out to about 24mm.
| | 01:10 | So I am going to take my shot here,
and now look at this picture. A lot has
| | 01:18 | changed between these two pictures.
| | 01:20 | In this second shot where I'm
standing closer to him and zoomed out, first of
| | 01:24 | all you can see the whole
building that's next to him.
| | 01:26 | In my more telephoto shot,
all you can see is this hedge.
| | 01:29 | Look at that tree in the
background in the first shot.
| | 01:32 | It seems like it's much closer to him
than in the second shot where first of
| | 01:35 | all it's obscured by his body and second, the
branches that you can't see up here very far way.
| | 01:40 | In other words, in the second shot
the entire sense of depth in the scene
| | 01:43 | is much more stretched.
| | 01:45 | The background feels much farther away
than it did in the first shot and that's
| | 01:48 | the general rule of thumb.
| | 01:49 | When you're standing farther away to
get a given image, you're going to have a
| | 01:53 | compression of the sense of depth in your
scene, because you're going to have to zoom in.
| | 01:57 | When you're standing closer and zoomed
out, you're going to have more of a sense
| | 02:01 | that the depth is stretched.
| | 02:03 | In other words, I can greatly
control the sense of space in the scene by
| | 02:07 | choosing where I'm going to stand and
therefore what focal length I'm going to use.
| | 02:11 | If I want to create a real intimate
sense of depth, then I probably want to stand
| | 02:15 | back there and zoom in.
| | 02:16 | If I want to create a more expansive
sense of depth, maybe even an outright
| | 02:20 | alienating sense of space in the
scene, then I'm going to want to stand
| | 02:23 | closer and zoom out.
| | 02:25 | So even though your zoom lens gives
you a great deal of flexibility and the
| | 02:29 | capability to reach far into the
distance to grab something, it's imperative
| | 02:33 | that you learn to pay attention to
this sense of space in your scene and
| | 02:36 | understand that where you stand and the
associated focal length that you choose
| | 02:40 | is going to greatly impact that sense of space.
| | 02:42 | I've talked here about depth compression and
depth expansion and all this kind of stuff.
| | 02:46 | It's great if you know that, but
know that you can just see it in the
| | 02:50 | viewfinder and you can see it when you
review your image on your LCD screen.
| | 02:53 | The thing to take away here is
to learn to pay attention to that
| | 02:56 | relationship between your foreground
and background and the overall sense of
| | 03:00 | space in the scene.
| | 03:01 | And know that you have control of that
relationship in sense of space by choosing
| | 03:05 | where to stand and what
focal length that to use.
| | 03:09 | Watch this. The camera operator is
pulling the camera backwards while
| | 03:14 | simultaneously zooming in with the
lens and trying to keep me framed the
| | 03:17 | same way the whole time.
| | 03:19 | Now watch the background. You should see
that wall behind me getting closer and closer.
| | 03:23 | This is exactly like what happened in
the two shots that we-- the two still images
| | 03:27 | that we took earlier in this movie.
| | 03:28 | As is camera position changes,
the sense of depth in the scene changes.
| | 03:33 | So because this is video you're
seeing each and every little step along the way,
| | 03:37 | but it's the same thing that was
happening to us when I was shooting stills earlier.
| | 03:40 | So again the thing to take away here is
where you choose to put the camera and
| | 03:44 | the associated focal length that you
have to use greatly impacts the sense of
| | 03:48 | space in your scene and the
overall sense of scale of the background.
| | 03:51 | So when you're setting up your shot,
be very careful to pay attention to the
| | 03:55 | background and pay attention to the way
the overall sense of space is rendered
| | 03:59 | in your final picture.
| | Collapse this transcript |
| Exercise: Taking ugly self-portraits| 00:01 | In the last video we looked at how
your choice of camera position and focal
| | 00:04 | length dramatically changes
the sense of space in your scene.
| | 00:08 | This was the whole business where I
shot a portrait of Ben out on the lawn in
| | 00:11 | front of a tree and there was a
building around, and as I moved around we saw
| | 00:14 | the tree get closer and farther.
| | 00:16 | In that example you might think, "Oh,
okay, I get it, in big spaces, there's a
| | 00:19 | big compression of depth or change of
sense of depth in the scene," and that's true,
| | 00:23 | but it's important to
understand that that depth compression, that
| | 00:27 | stretching and squashing thing, also
happens at a micro level on everything in
| | 00:31 | your scene, and this can really get
you when you're shooting portraits.
| | 00:34 | Here is what I mean. I'm going to
take a shot of him now and because I'm
| | 00:38 | standing kind of far away I've got to
zoom in. So I got my lens zoomed all the
| | 00:41 | way unto 105 millimeters and I'm
focusing on him and I'm taking my shot and if
| | 00:47 | you look at this picture,
we have a very nice portrait.
| | 00:50 | You can see that camera there in the
background looks a certain distance from him
| | 00:54 | and he has struck this very dramatic pose.
| | 00:56 | Now I'm going to shoot it again, I'm
going to move closer and because I'm moving
| | 01:01 | closer, if I want to frame the shot
in the same way, I've got to zoom out.
| | 01:05 | So again, my camera position
dictates a particular focal length if I want
| | 01:09 | a particular framing.
| | 01:11 | So I'm going to try and take what is
basically the same shot and here it is.
| | 01:18 | Now first off, look at
that camera in the background.
| | 01:21 | It looks like it's
farther away than it was before.
| | 01:24 | As we saw before, the entire sense
of space in the scene is different.
| | 01:27 | Things that were close up now appear
further away. There's been a change in the
| | 01:30 | depth compression in the scene.
| | 01:31 | More significantly though, look at his face.
| | 01:33 | It's completely different
from one image to the other.
| | 01:36 | His nose is bigger when I'm closer in
shooting wide-angle than it is here, where
| | 01:41 | I'm farther back and shooting telephoto.
| | 01:43 | In the telephoto shot, look at this, his
hair looks at it's much larger compared
| | 01:47 | to the wide-angle shot here, where it
looks like we've actually done something
| | 01:50 | to his hair, and you saw it. We didn't do
anything at all,.I just moved in closer.
| | 01:54 | The distance from his nose to ear
is different in the wide-angle shot.
| | 01:57 | His entire face has been stretched and
squished from one shot to another, and it
| | 02:01 | makes them look very, very different.
| | 02:02 | Now one is not necessarily right and
one is not necessarily wrong, but they are
| | 02:06 | very different images.
| | 02:07 | One is perhaps a little more flattering.
| | 02:09 | This wide-angle shot is possibly a
truer indication of his character.
| | 02:13 | The thing to understand here and
really notice is that where I stand and
| | 02:17 | my associated focal length really
has a huge bearing on how he looks.
| | 02:22 | That's why very often portrait
lenses are a particular focal length.
| | 02:26 | It's generally accepted that a good
portrait lens is one that's a little
| | 02:29 | bit longer than normal.
| | 02:31 | So on this camera, which has a full
frame sensor, normal focal length, that is
| | 02:35 | one that has the same field view of my
eye, is about 50 millimeters, so something
| | 02:38 | a little longer than that, usually
around at 80 to 85 is a nice portrait lens,
| | 02:42 | because that extra bit of telephotoness
will compress features some and that's
| | 02:47 | a little more flattering.
| | 02:48 | Also when you're looking for
portrait lens, you typically want to a fast
| | 02:51 | portrait lens, that is one whose
aperture can open very wide, because that's
| | 02:54 | going to give you the ability to
really blur out backgrounds and that shallow
| | 02:58 | depth of field you're going to be able
to get when you do that is possibly going
| | 03:00 | to soften skin tones a little bit.
Remember to keep the eyes in focus.
| | 03:04 | So the big lesson here is that the depth
compression that you have control of as
| | 03:09 | you choose different camera positions
and associated focal lengths is not just
| | 03:13 | about controlling the
sense of space in the scene.
| | 03:15 | It's also about controlling the amount
of distortion on people's faces or any
| | 03:20 | particular object that you're shooting.
| | Collapse this transcript |
| Shooting wide| 00:01 | As I stand here right now, I can see
an area of kind of reasonable focus
| | 00:05 | that's about this wide.
| | 00:06 | This is about the field of
view that my eye can deliver.
| | 00:10 | When I put a lens on my camera that
delivers about this field of view,
| | 00:13 | we call that a normal lens.
| | 00:15 | We've discussed this before. Lenses
that deliver a narrower field of view
| | 00:19 | are telephoto lenses.
| | 00:20 | Lenses that deliver a field of view
that's wider than what my eye could see is
| | 00:24 | considered a wide-angle lens.
| | 00:26 | I've got a wide-angle lens on my camera right here.
| | 00:28 | We're going to talk a lot about them right now.
| | 00:30 | Wide-angle lenses take a very wide
field of view and cram it into the frame.
| | 00:35 | A lot of people think, "Oh,
well, what wide angles are for are
| | 00:37 | when I see a big grand sweeping
distance, I really need a wide-angle lens to
| | 00:41 | capture all of that."
| | 00:42 | Problem is with wide-angle
lenses be sense of depth in your scene
| | 00:46 | is stretched very far.
| | 00:47 | So things in the distance are going
to be very, very, very, very, small.
| | 00:50 | And so wide-angle lenses are actually
not that great for capturing wide vistas.
| | 00:54 | Very often what I use them for the
most are places that might be a little
| | 00:57 | counterintuitive. Shooting indoors.
| | 00:59 | Trying to get angles that are a little
more interesting and delivers something
| | 01:02 | that my eye normally can't see.
Obviously there are some things you want to
| | 01:06 | shoot like maybe a mural that does
need a wide-angle to get the whole thing.
| | 01:09 | Sometimes you might be shooting an
event where they are indoors, where there
| | 01:12 | are simply too many people to fit in
the frame with a normal lens and so you
| | 01:16 | go to a wide-angle.
| | 01:18 | As you learn about the wide-angle
capabilities of your lens, it's really good
| | 01:21 | to start thinking about using it in
more situations and start practicing using
| | 01:25 | it in more situations than the ones
you may think are obvious wide-angle
| | 01:29 | situations, but that said, there are some
important things to know about wide-angle lenses.
| | 01:33 | I have on my camera right now a very
good 16 to 35mm lens. This camera has a
| | 01:39 | full frame sensor, so there is no
multiplication factor to that focal length.
| | 01:42 | This is exactly what a 16 to 35mm
lens would be on a 35mm film camera.
| | 01:47 | I am at the 16mm and wide right
now, which is very, very wide.
| | 01:51 | In general, you can assume that 28mm,
24 to 28 is what's considered a wide lens.
| | 01:57 | Anything shorter than that,
anything with a wider field of view is
| | 02:00 | considered an ultra-wide lens.
| | 02:01 | So I am on an ultra-wide lens right
now and let's take a look at what I
| | 02:04 | see through my camera.
| | 02:06 | I've got this tree here and you can see
that horizon line back there and I've
| | 02:11 | got the sky in the background.
| | 02:13 | Now I want you to notice
something about the horizon.
| | 02:15 | It's for the most part straight.
| | 02:17 | It dips a little bit on the edges
but that's because that particular part
| | 02:19 | of that ridge dips.
| | 02:21 | And look at the branches up there.
For the most part this looks like a pretty
| | 02:23 | clean image of a tree.
| | 02:25 | Now I'm going to tilt the camera up
and I want to watch the corners of the
| | 02:28 | frame, as I move the camera around
you can see the corners stretching, and
| | 02:34 | warping, and bending. That's wide-angle
distortion and you're not seeing a lot
| | 02:38 | of it on this lens,
because this is a very good lens.
| | 02:41 | But on a lesser lens you would see the
branches starting to crawl and bend at the edges.
| | 02:46 | When you're shopping for a wide-angle
lens, this is one of the things you want
| | 02:49 | to check out. Watch the corners as you
tilt the camera around and as you pan the
| | 02:54 | camera around. Here you can see
them stretching a little more as I pan.
| | 02:59 | If that stretching is happening a lot
you've got a lens with a tremendous
| | 03:01 | amount of distortion.
| | 03:02 | Another thing to look at here, watch the
horizon. As I tilt up and down, I'm not
| | 03:07 | getting -- the horizon is for
the most part staying straight.
| | 03:10 | It's not warping at the edges.
| | 03:12 | All of this means that this is a
very low distortion wide-angle lens.
| | 03:17 | Right now I'm zoomed up to 16mm.
| | 03:19 | This lens is a
rectilinear ultra-wide angle lens.
| | 03:23 | What that means is it's got elements in
it designed specifically to correct to
| | 03:27 | that distortion in the corner
and to keep the horizon straight.
| | 03:31 | It's trying to create as realistic an
image as it can, though it's very wide.
| | 03:35 | A wide-angle image is inherently
somewhat unrealistic and a little bit abstract,
| | 03:39 | but this is trying to keep the geometry in the
image as believable as possible. That's at 16 mm.
| | 03:44 | I'm not going to change to a
15 mm lens, only 1 mm difference.
| | 03:48 | However, this lens does not have--
this lens that I'm going to switch to, which
| | 03:52 | I have and I have right here.
| | 03:54 | This lens does not have any
rectilinear correction in it.
| | 03:57 | It's called a fisheye lens, and as
you can probably see the front element of
| | 04:01 | the lens here is really rounded
like the eye of a fish, I guess.
| | 04:05 | I don't know. I haven't spent a lot
time looking at fish eyes, but I'm going to
| | 04:09 | put it on my camera here.
| | 04:11 | And so I'm framed pretty much with the
same and if we look through the lens,
| | 04:16 | watch what's happening over here on the edges.
| | 04:18 | First of all notice that the field of
view is much wider, you can see one of the
| | 04:22 | lighting elements that we
have set up in this shot.
| | 04:25 | Now as I tilt the image up
and down, look at the horizon.
| | 04:29 | It's twisting and melting and getting
all surreal and look at the tree branches.
| | 04:33 | They're really, really, really moving around.
| | 04:36 | As I pan left and right, the tree is
almost like it's waving in the wind.
| | 04:40 | It's twisting and bending so much.
| | 04:43 | So this lens is, being a fisheye
lens, is not getting the benefit of
| | 04:47 | rectilinear correction.
| | 04:48 | So what it's got is a lot
of spherical distortion.
| | 04:52 | The image looks like it's mapped onto
or projected onto a sphere and as I pan
| | 04:56 | around I am looking around
the edges of that sphere.
| | 04:59 | That's not typically
something you want in a wide-angle lens.
| | 05:03 | Now fisheyes have their own applications.
There are a lot of fun images you can
| | 05:06 | take with a fisheye. Because the field
of view is so wide, sometimes it's the
| | 05:10 | only way to get certain types of images.
| | 05:12 | And if you're careful, you can still
try and shoot straight, horizontal, and
| | 05:15 | vertical lines. You've just got to be
very careful with your perspective.
| | 05:18 | So Fisheyes are great for
creating a very stylized look.
| | 05:22 | For a more general walk-around wide-
angle lens you want to be sure that you get
| | 05:25 | one with rectilinear
correction, something like this.
| | 05:28 | And again, that's the kind of thing you
can test very easily on a lens just by
| | 05:31 | going to a camera store, putting it
on your camera, and panning around and
| | 05:35 | watching the edges in the corners.
| | 05:37 | So if you do get yourself a nice
rectilinear wide-angle, there are still some
| | 05:41 | things to understand about how to shoot with it.
| | 05:44 | Though it's pretty clean as I pan
and tilt it around, there is still some
| | 05:48 | distortion. Lines are moving around a bit.
| | 05:51 | That means that as I'm shooting, very
often the difference between shooting like
| | 05:56 | this and shooting like
this can be pretty profound.
| | 05:59 | The difference between shooting
like this and shooting like this, or
| | 06:02 | shooting like this.
| | 06:03 | As you're shooting with a wide-angle
lens you want to be tilting it and panning
| | 06:06 | a little bit, because as you do you'll
be flattening out some shapes, stretching
| | 06:10 | others, distorting others, and that's
the kind of thing you'll really need to
| | 06:13 | pay attention to when you're shooting
wide. You're looking for distortion and
| | 06:16 | you're trying to control it.
| | 06:17 | Here is an example. I shot Ben again
here with the same focal length, with the
| | 06:22 | 16mm lens, but I had him tilt his chin
up and down and you can see that I'm
| | 06:27 | getting a very different level of
distortion on his nose and his face is kind of
| | 06:32 | twisting and stretching in a
different way from one shot to another.
| | 06:35 | One is potentially a little
more flattering than the other.
| | 06:38 | It's something that you just need to
pay attention to while you're shooting.
| | 06:40 | So when you're working with wide-angles
you've got to be really careful to watch
| | 06:43 | the edges and watch your lines.
| | 06:45 | It's something you can get very practiced at.
| | 06:47 | And for the most part the
movements you need to make are very slight.
| | 06:51 | Now we're talking about ultra wide-
angle lenses here. All of that's still true
| | 06:54 | with not so wide-angle lenses like 28 mm,
35 mm, but still keep an eye out for
| | 06:59 | that when you work with your wide angles.
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| Shooting telephoto| 00:01 | When you shoot telephoto, whether
you're shooting sports or shooting nature or
| | 00:05 | just spying on your neighbors, you're
capturing a very narrow crop of the world.
| | 00:12 | One of the tricky things about shooting
extreme telephoto is that when you take
| | 00:16 | that very narrow crop of the world,
it's very easy to see when that crop is
| | 00:20 | moving around. That can make
it very difficult to frame.
| | 00:22 | It's hard to really get
zeroed in on the bit that you want.
| | 00:24 | Well, what's more, as you learned in the
Foundations of Photography Exposure course,
| | 00:29 | it can require a much shorter shutter speed
when you're shooting at extreme telephoto.
| | 00:34 | As you'll recall, the handheld shutter
speed rule says that your shutter speed
| | 00:39 | when shooting handheld should never
drop below 1 over your focal length.
| | 00:43 | So I have here a 70-200 millimeter zoom
lens and right now I'm putting it on a
| | 00:49 | focal length of 100.
| | 00:51 | According to the handheld shutter speed
rule that means my shutter speed should
| | 00:54 | not go below 1/100th of a second.
| | 00:56 | If it does, I'm going to risk camera
shake, which is going to blur my image.
| | 01:01 | Now if you're using a camera that
has a crop factor, if you're using a
| | 01:05 | camera that has say like a Canon
camera that has a 1.6x multiplier or a
| | 01:09 | Nikon camera that has a 1.5.
| | 01:10 | Let's say I'm shooting with a 1.6.
| | 01:13 | This lens at this focal length
is actually a 160 millimeter lens.
| | 01:17 | That means that my shutter speed should
not go below 1/160th of a second or I'll
| | 01:22 | be risking handheld shake.
| | 01:25 | Now fortunately these days there's
an amazing technology called optical
| | 01:29 | image stabilization.
| | 01:31 | The way optical image stabilization
works is, as you've already learned a lens, a
| | 01:35 | camera lens is actually composed of a
bunch of different lenses, some of them
| | 01:39 | cemented together into groups.
| | 01:40 | The last one over here is built in a way
so that it can change its shape or move
| | 01:45 | around so that as I jitter the lens
this way, it can change its shape to bounce
| | 01:50 | the light back in the same amount the
opposite direction to even out shake.
| | 01:55 | Now, this is not a substitute for a tripod.
| | 01:57 | I'm not going to be able to even out
riding in the back of a jeep or something.
| | 02:01 | But as far as just evening out the
kind of handheld shake that you get just
| | 02:04 | from being alive, it can take care of
that and really smooth out your images.
| | 02:10 | So this is a 75-300 millimeter lens
that has a stabilizer and I know that
| | 02:14 | because there is this big
stabilizer switch right here.
| | 02:16 | I can turn the stabilization on and off.
| | 02:19 | Stabilizers are rated in terms of stops.
| | 02:22 | So let's say for example that the
manufacturer claims four stops of
| | 02:26 | stabilization on this lens.
| | 02:29 | That means that if I'm shooting at a
focal length of 100, when I'm calculating
| | 02:36 | my handheld shutter speed rule, I can
go down four whole stops to find out what
| | 02:41 | my minimum shutter speed
is for shooting handheld.
| | 02:44 | So a stop is to-- going
down a stop means to halve.
| | 02:48 | So 100 divided by 2 would be 50.
| | 02:50 | That's one stop, 125th would be two
stops, a 12th would be three stops, a 6th
| | 02:56 | would be four stops.
| | 02:57 | That means I could go down to a 6th
of a second and still shoot handheld.
| | 03:01 | Let's assume that 4th stop is more of a
marketing claim and that it only kind of
| | 03:06 | works on a test bench and go back to 3 stops.
| | 03:09 | So I could shoot probably
pretty safely at a 12th of a second.
| | 03:12 | Now at that speed, things that are
moving around in my frame, they are still
| | 03:16 | going to be blurry, but I'm
not going to have handheld shake.
| | 03:20 | This is a fairly simple stabilization mechanism.
| | 03:23 | Also, Nikon shooters know that Nikon
calls this technology vibration reduction.
| | 03:29 | So you'll see VR lenses rather than IS lenses.
| | 03:32 | those are the lenses that have
stabilization and like the Canon stabilization,
| | 03:36 | Nikon stabilization is excellent.
| | 03:39 | Here's a lens with a more complex stabilizer.
| | 03:43 | So I've still got my stabilizer on/off
switch here for turning stabilization
| | 03:47 | completely off if I want, but I
also have the Stabilizer Mode.
| | 03:51 | So when I'm in Mode 1, the
lens is completely stabilized.
| | 03:55 | It stabilizes any little
bit of shake that I do to it.
| | 03:58 | When I switch to Mode 2,
it only stabilizes one axis.
| | 04:02 | The point here is that when I pan,
my pan is kept stable on the vertical axis,
| | 04:08 | but there's no stabilization
applied to the horizontal axis.
| | 04:10 | I don't want to trying to even out
movements that I'm making this way, because
| | 04:14 | I'm actually trying to move the lens that way.
| | 04:16 | I am going to show you another switch on
this lens that-- We're going to come back
| | 04:20 | to stabilization in a second.
| | 04:21 | This is about focus.
| | 04:22 | This lens is interesting, because
it's got these two different focus modes.
| | 04:25 | This switch says 2.5 meters to infinity and
over here I've got 1.4 meters to infinity.
| | 04:31 | This allows me to kind of
optimize the auto focus on this lens.
| | 04:35 | Because this is a long lens, there are
going to be times where I'm probably only
| | 04:39 | worried about shooting things and
focusing things that are really far away.
| | 04:42 | So if I know that I'm not going to be
shooting any closer than 2.5 meters,
| | 04:46 | you can flip the switch over to 2.5 meters
to infinity and that will make you auto
| | 04:50 | focus faster, because it won't
bother searching in that closer range.
| | 04:54 | That's going to give me a
slightly faster auto focus mechanism.
| | 04:58 | Here is another example that's kind of cool.
| | 04:59 | This is a macro lens.
| | 05:03 | So there are times where I'm going
to be shooting really close with it.
| | 05:05 | It's actually got three switches.
| | 05:07 | I can tell it Full, which means "Oh,
| | 05:10 | mighty lens, when you're searching for
auto focus, search through the entire
| | 05:13 | range of focus" or go down to only
searching for half-a-meter to infinity or if I
| | 05:19 | know that I'm going to be just working
really close up, which I tend to do a lot
| | 05:22 | with a macro lens, only look for
focus between 0.3 and 0.5 meters.
| | 05:28 | So this is a way of really refining my focus.
| | 05:30 | It's never even going to try to focus
on infinity, which will save me a lot of
| | 05:33 | hassle with the lens isn't suddenly going
to go way out of focus, and notice that this
| | 05:37 | also has a stabilizer, which is very
important, because when you're shooting macro,
| | 05:41 | you're in really close and you
don't want it? you want the camera?
| | 05:44 | you want the lens stabilized.
| | 05:45 | That's why there's a stabilizer.
| | 05:47 | So one of the most important things
to know about stabilization as you've
| | 05:50 | already seen is that I can turn it off,
because stabilizing takes battery.
| | 05:55 | When you put the stabilizer on your
camera or when you put the lens on your
| | 05:57 | camera, the first time you press that
shutter button, you'll probably really
| | 05:59 | notice that when you half press,
the lens starts doing something.
| | 06:03 | There's a little kind of whir sound as
it starts stabilizing and you should see
| | 06:07 | the image in the viewfinder sharpen up.
| | 06:09 | Some point and shoot cameras have
optical image stabilization and it's the same
| | 06:14 | technology that's in a big lens like this.
| | 06:16 | But point and shoot cameras also often
have digital stabilization and that's
| | 06:20 | where it takes the frame and actually
tries to just digitally crop the frame and
| | 06:24 | move it around to keep it stable.
| | 06:26 | You don't want digital stabilization.
| | 06:28 | It can very much degrade your image
and it doesn't work nearly as well as
| | 06:31 | optical image stabilization.
| | 06:33 | Fortunately a lot of
vendors have abandoned that.
| | 06:35 | If you do have it, there is a way to
turn it off and you should do that.
| | 06:38 | Some camera vendors issue lens
stabilization and instead stabilize the sensor.
| | 06:45 | The sensor itself can move
around to compensate for movement.
| | 06:48 | Olympus cameras use this. Sony
SLRs use image stabilization or image
| | 06:53 | sensor stabilization.
| | 06:54 | What's nice about that is any lens that
you put on the camera ends up stabilized.
| | 06:58 | What can be a downside to sensor-
based stabilization is in some cameras you
| | 07:03 | don't see the effects of the
stabilization in the viewfinder, so you don't get
| | 07:06 | the advantage of having ease of framing.
Because the stabilization is basically
| | 07:11 | downstream of the viewfinder.
| | 07:12 | So when you're hunting for a lens, you
want to pay attention to stabilization.
| | 07:16 | It's a great feature to have and
stabilization technology from pretty much every
| | 07:21 | vendor these days is so great.
| | 07:23 | It's really worth investing that
little bit of extra money, particularly when
| | 07:26 | you're working on the telephoto end.
| | 07:28 | This is my 24-105 millimeter lens.
| | 07:31 | It's my walk-around lens.
| | 07:32 | And look, it's even stabilized, which is
great, because even at 105 millimeters
| | 07:36 | there is a time that I could, times
when I could suffer from camera shake.
| | 07:39 | If you're looking for a wide angle lens,
you're not going to find one that's
| | 07:43 | stabilized because there's simply no need.
| | 07:44 | When you're framed out really wide,
you're just not going to notice if there's a
| | 07:48 | lot of camera shake.
| | 07:49 | So if you've been hunting for a 16-35
say that's stabilized, you're probably
| | 07:52 | not going to find it.
| | 07:53 | But notice that stabilization is not
just for giant lenses. Even a walk-around
| | 07:57 | lens can benefit from it.
| | 07:59 | So check your camera's manual to
learn the details of your particular
| | 08:02 | lens' stabilization or your camera's
stabilization feature if your sensor is stabilized.
| | Collapse this transcript |
| Focal length applications| 00:01 | Lenses come in a huge variety of focal lengths.
| | 00:04 | You can get zooms, you can get primes,
you can get lenses that have incredibly
| | 00:08 | short very wide-angle focal lengths,
preposterously long, extremely telephoto
| | 00:12 | focal lengths, and everything in between.
| | 00:15 | So, why would you choose one over the other?
| | 00:16 | Why is there such a vast
assortment of focal lengths?
| | 00:20 | Depending on how much you have been
shooting, you might already have some ideas
| | 00:23 | about the answer to this question.
| | 00:24 | You might already be favoring one
focal length range over another, or maybe
| | 00:28 | you are just shooting with what you have with
no idea of what some of the other options are.
| | 00:33 | You can shoot any image with any type
of lens but in general, the application
| | 00:37 | for particular focal length
ranges breaks down something like this.
| | 00:41 | You got your extreme telephoto lenses,
which give you a tremendous reach and
| | 00:46 | allow you to tightly frame
things that are very far away.
| | 00:48 | These are great for sports or nature
shooting or some types of adventures.
| | 00:52 | This is a rather extreme
example of extreme telephoto.
| | 00:56 | There are shorter telephoto lens is such
as this 70 to 200, which can be great for
| | 01:01 | some types of event shoots and nature
shooting and occasionally even candid,
| | 01:05 | everyday, or street shooting.
| | 01:08 | There is midrange lenses like this 24 to 105.
| | 01:11 | These are your everyday walk around
lenses that can go wide enough for shooting
| | 01:16 | in tight indoor spaces but with a tiny
bit of telephoto reach that you don't
| | 01:20 | have to get right in people's faces.
| | 01:22 | Wide-angle lenses, these are going to
be the 24 millimeter to 35 millimeter
| | 01:26 | lenses that are great for street
shooting, interior shooting, anytime when you
| | 01:30 | want a wider perspective or dramatic angle.
| | 01:33 | Then there are the super wide angles,
pretty much anything wider than 24
| | 01:38 | millimeter falls into this category.
| | 01:39 | These deliver an extreme view of the
world, which can be great for times when
| | 01:43 | you need to cram a lot of stuff in
the frame or when you want to create a
| | 01:46 | somewhat stylized image.
| | 01:48 | We'll have a lot more to say
about super wide lenses later.
| | 01:51 | Once you've identified the type of lens,
you think you might be interested in,
| | 01:54 | there are a lot of questions to
answer and parameters to consider.
| | Collapse this transcript |
|
|
4. Depth of FieldDepth of field (DOF)| 00:01 | You should already be comfortable
with the concept of depth of field and
| | 00:04 | understand how aperture choice
impacts the depth of field in an image.
| | 00:08 | If you're not, then go watch the
Foundations of Photography: Exposure course or
| | 00:14 | at least the depth of
field and aperture bits of it.
| | 00:16 | To shoot shallower depth of field,
you need to use a wider aperture.
| | 00:20 | One that has a lower f-stop number.
| | 00:22 | So f/2.8 yields an image with
less depth of field than f/11.
| | 00:27 | Now the thing is not all lenses can open
their aperture all the way to f/2.8.
| | 00:33 | For all sorts of complex physics and
optical reasons, the lens has to be engineered
| | 00:37 | specifically to manage an
aperture of a particular size.
| | 00:41 | This means that every lens has a maximum
aperture size to which it can be opened
| | 00:46 | and that size is written
on the front of the lens.
| | 00:48 | For example, here is a 50mm lens
that has a maximum aperture of f/1.8.
| | 00:54 | I know that because right here it says 1:1.8.
| | 00:59 | Maximum aperture is often
expressed as a ratio like this.
| | 01:03 | Now check this out.
| | 01:04 | This is also a 50 millimeter lens but its
maximum aperture is 1.2, as I can see here.
| | 01:12 | Now plainly, the 1.2 lens is much
larger than the 1.8 and what you can't
| | 01:17 | see just from watching is that it's also a
lot heavier and it's a lot more expensive.
| | 01:21 | We refer to the maximum aperture of
the lens as the speed of the lens.
| | 01:26 | So, if someone says, "What speed is that lens?"
| | 01:28 | I would say, "Oh it's a 1.2," and they'd
slink off, done in by the status conveyed by
| | 01:34 | this very fast lens I am holding.
| | 01:36 | With a faster lens, I can use faster
shutter speeds because of the ability to
| | 01:40 | open the aperture wider.
| | 01:42 | Now, you can think of a faster lens as
being able to gather more light in the
| | 01:47 | same amount of time as a slower lens.
| | 01:49 | It takes a lot of glass to make a
faster lens and it has to be very
| | 01:53 | high-quality glass.
| | 01:54 | And that's why a faster lens like this
is bigger and more expensive than even
| | 01:59 | just a slightly slower lens like this one.
| | 02:02 | With a fast lens, I can shoot very
shallow depth of field and I can also shoot
| | 02:06 | in lower light while keeping my
shutter speed fast enough both for hand-held
| | 02:09 | shooting and to stop moving action in my scene.
| | 02:13 | Now, zoom lenses also have
maximum aperture ratings.
| | 02:18 | So for example, this 24 millimeter
to 105 millimeter lens has a maximum
| | 02:23 | aperture of f/4, which I can see right here.
| | 02:27 | Other zoom lenses might show an aperture range.
| | 02:30 | For example, this 18 millimeter to
55 millimeter lens, which is a fairly
| | 02:34 | typical kit lens that might be bundled with a
camera, shows an aperture range of 3.5 to 5.6.
| | 02:41 | Now, that means at full wide angle,
the maximum aperture that you can get with
| | 02:46 | this lens is at 3.5.
| | 02:48 | At full telephoto, zoomed in all the way,
| | 02:51 | the maximum aperture is at 5.6.
| | 02:54 | Focal lengths in between vary between
f/3.5 and f/5.6. Smaller zoom lenses like
| | 03:01 | this often have a variable maximum
aperture across their range, because that's
| | 03:04 | the only way to engineer that focal
length range in such a small package.
| | 03:09 | Now, here is a 75 millimeter to 300
millimeter lens and here is a 70 millimeter
| | 03:17 | to 200 millimeter lens.
| | 03:19 | Now this 70 millimeter to 200
millimeter has a shorter zoom range than this 75
| | 03:23 | to 300, but it's physically larger
than the lens with the larger range. Why?
| | 03:28 | Well, the 75mm to 200mm,
excuse me, the 70mm to 200mm is faster.
| | 03:33 | The 75mm to 300mm shows a
maximum aperture of f/4 to f/5.6.
| | 03:39 | Now, again, that means that at the
wide angle, my maximum aperture is f/4.
| | 03:43 | If I zoom all the way into full
telephoto, then my maximum aperture can only
| | 03:47 | open to f/5.6. By comparison, this 70mm
to 200mm has a maximum aperture of f/2.8.
| | 03:55 | Sometimes the maximum aperture is also
written here on the outside of the lens.
| | 03:58 | Now, that's much faster and this
lens has that maximum aperture across
| | 04:03 | its entire zoom range.
| | 04:05 | As I mentioned earlier, fast lenses
are expensive and fast zoom lenses
| | 04:09 | especially. Fast zoom lenses like this
one that are fast across their entire
| | 04:12 | range, those are especially expensive.
| | 04:14 | For most everyday shooting though a
3.5 to 5.6 maximum aperture is probably fine,
| | 04:19 | but it's still nice to
have a fast lens in your arsenal.
| | 04:24 | If you're a Canon or a Nikon shooter
on a budget, you should know that both
| | 04:28 | companies make very good, very inexpensive
f/1.8, 50 millimeter lenses, like this one.
| | 04:34 | Now this thing feels cheap.
| | 04:36 | It feels plasticky, but it's got great
glass in it and you can get either one of
| | 04:40 | these for under 100 bucks.
| | 04:42 | They are small, they are light.
| | 04:43 | So, it's worth keeping one in your bag
just for those times when you need a fast lens
| | 04:47 | because you want to shoot shallow
depth of field or you want to shoot in
| | 04:50 | lower light, and your other
lenses are all in the 3.5 to 5.6 range.
| | 04:55 | Now, as you'll see in the rest of
this chapter, lens speed is not the only
| | 04:59 | factor that controls depth of field.
| | Collapse this transcript |
| DOF and sensor size| 00:01 | We've already talked about how some
cameras have smaller sensors than others,
| | 00:05 | and how sensor size impacts field of view.
| | 00:07 | But sensor size also has
an effect on depth of field.
| | 00:11 | Smaller sensors inherently have more
depth of field than larger sensors.
| | 00:15 | That means that you cannot achieve as
shallow a depth of field with a camera
| | 00:19 | with a smaller sensor as you can
with a camera with a larger sensor.
| | 00:24 | Here's an image shot with a full
frame digital SLR using an f/1.2 lens.
| | 00:29 | It has extremely shallow depth of field.
| | 00:32 | By comparison, here is an image shot
with a typical point-and-shoot camera.
| | 00:36 | While the background is a little soft, it's
not nearly as soft as the image from the SLR was.
| | 00:41 | This is about as shallow as you can
hope to go with a point-and-shoot camera.
| | 00:45 | Now, there are advantages to the
inherent deep depth of field of smaller sensors.
| | 00:50 | If I am shooting with a point-and-
shoot camera, I don't have to worry as much
| | 00:53 | about everything being in focus.
| | 00:55 | This is great for landscape shooting.
| | 00:57 | It's great for times when my subject is
moving in and out relative to my camera position.
| | 01:02 | So for quick shooting, for landscape stuff,
having a smaller sensor can be a good thing.
| | 01:09 | If I am wanting to shoot portraits
with really soft buttery backgrounds,
| | 01:12 | this isn't going to be the best choice.
| | 01:14 | With SLR, we've already looked at how
some SLRs have smaller sensors than others.
| | 01:19 | The cropped sensor cameras that have
a sensor that's the size of a piece of
| | 01:22 | APS film, those have inherently
deeper depth of field than a camera with a
| | 01:26 | full frame sensor, that is one that has
a sensor that's the size of a piece of
| | 01:30 | 35 millimeter film.
| | 01:32 | So, again if you're really finding
that shallow depth of field is something
| | 01:36 | that you would like to regularly use, then
you may need to consider your camera choice.
| | 01:39 | If you're an all in focus all the time type
person, then a smaller sensor is great for you.
| | 01:44 | If you want the ability for shallower
depth of field, you're going to want to
| | 01:47 | consider a camera with a bigger sensor.
| | Collapse this transcript |
| DOF and background size| 00:01 | By now you should be pretty
comfortable with the understanding that wider
| | 00:04 | apertures yield shallower depth of field.
| | 00:07 | But think about this. This is kind
of our fortune cookie moment here.
| | 00:11 | If a tree in the forest is out of focus
because of shallow depth of field and no
| | 00:15 | one is around to see it,
is it actually out of focus?
| | 00:18 | Here is what I'm taking
about and why this is relevant.
| | 00:20 | Things in the background appear softer
when you're using a wide aperture but if
| | 00:24 | there isn't anything in the background
or if what's in the background is really small,
| | 00:28 | then you're not really going to
be able to tell that you're shooting with
| | 00:30 | shallow depth of field, now are you?
| | 00:32 | Usually the point of shooting with
shallow depth of field is to blur the
| | 00:35 | background out to bring
more attention to your subject.
| | 00:38 | But if there is nothing in your
background, it won't really matter what
| | 00:41 | aperture you are at because you won't be able
to see that anything in the frame is defocused.
| | 00:45 | So when you're trying to achieve
shallow depth of field you need to think a lot
| | 00:49 | about camera position and focal length.
| | 00:51 | As you've seen, this sense of depth in
your scene changes as you move your camera
| | 00:56 | closer to and farther away from your subject.
| | 00:59 | You can choose the camera position and
focal length that make your background
| | 01:02 | appear closer or farther.
| | 01:04 | If you're trying to achieve an image
with shallow depth of field, you'll be
| | 01:07 | better served by standing farther from
your subject and using a more telephoto lens,
| | 01:12 | because background objects will
be rendered larger than when you use a
| | 01:16 | wide angle lens and stand close to your subject.
| | 01:18 | If the background is larger,
defocusing of the background will be more
| | 01:22 | obvious. Here is an example.
| | 01:24 | Here is a shot taken while standing fairly
close to the subject using a wide-angle lens.
| | 01:28 | Yes, the background is a little soft
but this image doesn't have that shallow
| | 01:31 | depth of field that makes the
background appear really thrown into blurriness.
| | 01:36 | Here I moved back and zoomed into a
longer focal length and frames to make
| | 01:40 | the background larger.
| | 01:41 | This image looks like it has shallower
depth of field. In fact the amount of
| | 01:45 | softening in the background in both
images is identical, but because the
| | 01:49 | mountain appears closer,
it's easier to see that it's out of focus.
| | 01:53 | If you'd like to see a more detailed
discussion of this example and watch while
| | 01:56 | I actually take these shots, check
out the Foundations of Photography: Exposure course,
| | 02:00 | more specifically Chapter 5, movie 6.
| | Collapse this transcript |
| Deep DOF and diffraction artifacts| 00:01 | To capture a really deep depth of
field you use a smaller aperture, bigger-up number.
| | 00:05 | This should be basic exposure
theory that you're already comfortable
| | 00:08 | with as well as an understanding that
where you focus when you're trying to
| | 00:12 | shoot deep depth of field
matters. We covered this earlier.
| | 00:15 | I want to talk to you now about how
after a point closing your aperture down
| | 00:20 | might actually soften your image a
little bit due to an optical phenomena
| | 00:24 | and called diffraction.
| | 00:25 | Basically it works like this. As you
close the aperture down to a smaller hole,
| | 00:29 | when the light gets squeezed through
that hole, it gets diffractive, knocked
| | 00:32 | around a little bit, and
it ends up getting softened.
| | 00:34 | It doesn't focus as sharply as it should.
| | 00:37 | Now, what we're about to demonstrate and
show is a pretty finicky level of sharpness.
| | 00:44 | Sharpness is a very subjective thing.
| | 00:48 | Opticians typically refer to it as
acceptable sharpness, meaning everyone has
| | 00:52 | a different idea of what's sharp and what's not.
| | 00:55 | Sharpness and how much it matters
also depends on how you're outputting.
| | 00:59 | If you're printing something small
like a 4x6 from a 16 megabyte image,
| | 01:04 | sharpness is probably not going to be
that critical in-camera because you're
| | 01:07 | going to pick up so much
sharpness when you sized down.
| | 01:10 | Nevertheless I think it's
interesting for you to see how this works.
| | 01:12 | I have a test target down here.
| | 01:14 | it's just a simple resolution target.
| | 01:16 | I put my camera in Aperture Priority
mode and I'm going to shoot it on several
| | 01:21 | whole-stop apertures, making
the aperture smaller each time.
| | 01:24 | I've connected a remote control to my camera
| | 01:25 | because I want to be sure that
I'm not getting any camera shake.
| | 01:28 | So right now I'm set in on a 5.6.
I'm going to just take that picture.
| | 01:32 | And just frame kind of
tightly on that subject there.
| | 01:34 | I'm going to go up to
8 and take another picture.
| | 01:39 | I'm waiting a moment after handling the
camera to be sure that it's got time to
| | 01:43 | stop vibrating. There is 11.
| | 01:45 | And the reason I'm concerned about
vibration is we're talking about sharpness
| | 01:48 | differences here that could be
impacted by a camera movement.
| | 01:51 | I'm up to f16 and I'm
going to do one more at f22.
| | 01:58 | Now a lot of times when you trying to
shoot deep depth of field, you think, "Oh,
| | 02:00 | I'm just going to close my aperture down
as far as it will go and that will give
| | 02:03 | me really deep depth of field" and it will.
| | 02:05 | But look at this. Here's the image shot
at f5.6. Notice the edge, one of those
| | 02:10 | black & white edges.
| | 02:11 | I've zoomed in here to
100%. Now look at it at f22.
| | 02:16 | You should see there's a little bit
of softness in the f22 image that's not
| | 02:21 | there in the f5.6 image.
| | 02:23 | That is diffraction artifacts.
| | 02:26 | That is not going to be true with every lens.
| | 02:28 | That's this particular lens, which is the
kit lens that came with this camera, but
| | 02:32 | if I put better lens on
there I may not see that.
| | 02:35 | Another question is whether that level
of softening matters in the real world.
| | 02:38 | And again, this type of sharpness
discussion is a really subjective thing and
| | 02:43 | it's kind of up to you to decide
whether you think that that's a level of
| | 02:46 | softening that matters.
| | 02:48 | Before you can make that decision though,
you need to know how your lens responds.
| | 02:51 | There is no problem to Google around
and find yourself a test chart, print it
| | 02:55 | out on your printer, and
do just what I've done here.
| | 02:56 | Set it up in some nice light. We're
not having to be that careful about how
| | 03:00 | we're taking a picture.
| | 03:00 | I've over exposed by about a stop to
get my brightness levels up to where
| | 03:04 | they need to be, and you saw that
I'm just controlling aperture and taking
| | 03:07 | these shots, taking them into my image
editor, and looking at them at 100% to see
| | 03:12 | how sharp they are.
| | 03:14 | Next do the same thing
with a real world example.
| | 03:17 | Go and take a landscape shot or
something that has some fine detail in it and
| | 03:20 | see if the level of sharpness
changes in a way that really matters.
| | 03:23 | For really sturdy test you might then
want to do some output. Maybe print some
| | 03:26 | pictures and see if you can tell a difference.
| | 03:28 | You may find that this is not a
factor at all in your shooting.
| | 03:32 | The important thing to know is that, it
is a potential weakness in your lens and
| | 03:36 | you want to test your lens to find out
if your lens possibly has a diffraction
| | 03:40 | issue that could cause you some
sharpness that you're not willing to lose.
| | Collapse this transcript |
|
|
5. Choosing a LensChoosing a lens| 00:01 | Since we've been talking so much about
how to use particular types of lenses,
| | 00:04 | you may be thinking about adding another
lens to your arsenal or upgrading to a
| | 00:08 | higher quality lens.
| | 00:09 | We're going to take a break from the
specifics of shooting for a bit and talk
| | 00:12 | about choosing a lens.
| | 00:14 | Even if you don't have an SLR but
shoot with point-and-shoot cameras, you'll
| | 00:17 | still want to give a thought to
assessing a candidate camera's lens.
| | 00:20 | So, the following discussion
should still prove helpful.
| | 00:23 | Your first concern when lens shopping
is to think about what it is you need.
| | 00:27 | And first and foremost in
that decision is focal length.
| | 00:30 | And if you have no idea what focal
length you need, one, it may not be time to
| | 00:35 | start shopping for a new lens.
| | 00:36 | But your camera probably came
with a kit lens of some kind
| | 00:40 | That's a zoom lens that has a focal
length range from may be a little bit wide
| | 00:44 | to a little bit telephoto.
| | 00:45 | Think about how you've been shooting.
| | 00:46 | Do you spend more time with the, at
the telephoto end, because you like
| | 00:50 | shooting things that are farther away?
Do you spend more time in the wide angle
| | 00:53 | lens because you are-- at the wide angle
end of things, because you're shooting indoors?
| | 00:59 | In either case, are you finding
yourself lacking at some point with the if
| | 01:03 | you tend to shoot more with the telephoto lens,
at the telephoto end, are you thinking "Gosh!
| | 01:07 | I wish I just had a little more reach.
I can't quite see that thing over there."
| | 01:10 | If you shoot more the wide angle
end of things, do you spend more time
| | 01:14 | thinking "Ugh, I just need a lot, I am
having to shoot more panoramas," or "I can't
| | 01:17 | quite fit things in my scene."
| | 01:19 | That's an indication that you might have a
particular preference of one kind or another.
| | 01:23 | Or maybe you're just
frustrated with the quality of your lens.
| | 01:26 | Maybe it's not as sharp as you would like.
| | 01:27 | Maybe there are strange
colored fringes around things.
| | 01:31 | Those are all indications that you've
outgrown the quality of your lens and
| | 01:34 | maybe you want to upgrade.
| | 01:35 | So, your first choice is
what focal length do you want?
| | 01:38 | So, after you zeroed in on one end
of the spectrum or another, your next
| | 01:42 | really major decision should be to
really get a good strong idea of how much
| | 01:46 | you're willing to pay.
| | 01:47 | Because once you've narrowed down to a
price point, you're going to cut a whole
| | 01:50 | lot of lenses out of consideration and
that's going to make your choice easier.
| | 01:54 | And don't waffle on that.
| | 01:55 | Don't say "Well, you know,
maybe from here to here."
| | 01:57 | Get a good solid idea of a price
point so that you're not looking at a lens
| | 02:00 | thinking, "Well, if I just
spend $300 more, I could get this."
| | 02:04 | Because the problem is when you do that
| | 02:05 | then you think, "But if I just spend $
300 more than that" and then you've talked to
| | 02:08 | yourselves into a lens that's maybe more
than you can afford or even more than you need.
| | 02:12 | So, you got an idea what
you're willing to spend.
| | 02:13 | You got an idea of what type of
focal length you're looking for.
| | 02:17 | Your next consideration is
going to be zoom versus prime.
| | 02:20 | Prime lenses have a fixed focal length.
| | 02:23 | Zoom lenses have a variable focal length.
| | 02:25 | And 15 years ago, if you were talking
about buying a zoom lens, just about any
| | 02:29 | serious photographer would have said,
| | 02:31 | "Oh! You don't care that much
about image quality, do you?"
| | 02:33 | And of course, image quality should be
your primary concern when choosing any lens.
| | 02:37 | But that was then and this is now.
| | 02:38 | Today, thanks to computerized design
and manufacturing of lenses, zoom lenses
| | 02:43 | can deliver image quality that's
just as good as primes. Almost.
| | 02:47 | Primes will still eke out a
little more sharpness sometimes.
| | 02:51 | So for example, maybe you've decided
that you're looking for something like a
| | 02:54 | 50 millimeter lens.
| | 02:55 | So, here is a 50 millimeter prime lens.
| | 02:59 | But I could also go for something
like this, 24 to 70, which gives me a
| | 03:03 | 50 millimeter lens, but also a little bit
of wide-angle and a little bit of telephoto.
| | 03:07 | And it might be higher quality than the
kit lens that I came with. How do I choose?
| | 03:12 | Well, if you're a real stickler for
sharpness, may be the prime is a better way to go.
| | 03:16 | But another parameter is going to
be kind of your next choice, which is
| | 03:20 | speed consideration.
| | 03:22 | How wide an aperture do you
want to be able to open to?
| | 03:25 | This lens can open to 1.2.
| | 03:27 | This can only open to 2.8.
| | 03:28 | This is still a fast lens, but if you
really like shallow depth of field or
| | 03:32 | shooting in really low light,
this is the faster lens.
| | 03:34 | So, if all you were thinking of was a 50,
then maybe you want to go for a faster one.
| | 03:38 | If you're not that concerned about speed
and you think 2.8 is fast enough, then
| | 03:42 | maybe this is a better way to go,
because it gets you some extra zoom range.
| | 03:47 | Another thing to consider is with
speed you're probably going to find,
| | 03:52 | particularly with something like a
50, here is a 50 1.2, here is a 50 1.8.
| | 03:57 | Canon also makes a 50 1.4,
which we don't have here.
| | 04:01 | Right away, you might start finding
yourself facing a number of lenses that
| | 04:04 | seem pretty similar.
| | 04:05 | 1.2, 1.8, that's like a
stop and a half difference.
| | 04:09 | You're going to want to think about do you,
do you care about that extra stop and a half?
| | 04:13 | This lens is heavier,
maybe that's a consideration.
| | 04:15 | This lens is about $1500.
| | 04:17 | This lens is about $300 to $400.
| | 04:19 | That might make the
decision for you right there.
| | 04:21 | So, part of lens buying is always
going to be balancing these different
| | 04:25 | parameters and trying to figure
out what the right combination is.
| | 04:28 | Again, image quality
should be your main concern.
| | 04:31 | So, you're going to be wanting to
evaluate the lenses for overall sharpness,
| | 04:35 | vignetting, chromatic aberration,
a lot of things we've talked about in other
| | 04:39 | places in the course.
| | 04:40 | There are some practical concerns also.
| | 04:43 | So, maybe you've decided on a price
point, you figured out that type of lens
| | 04:46 | you're looking for, you've decide
it's definitely zoom in this range.
| | 04:51 | Because of my price point, I've weeded
out the very high end and the very low end.
| | 04:54 | I am going for a nice mid-range
lens. You've winnowed it down that way.
| | 04:57 | You still might find yourself facing a
few candidates, particularly if you to
| | 05:00 | start considering third-party lenses.
| | 05:03 | Canon and Nikon, Olympus, Pentax, they
all make great lenses for their cameras,
| | 05:08 | but there are other companies. Sigma, Tamron.
| | 05:11 | They make very good lenses.
| | 05:13 | Now the, the brand loyal
snobs will say, "Oh my gosh!
| | 05:16 | You should never stick up a non-Canon
lens on your Canon body or non-Nikon
| | 05:21 | lens on your Nikon body."
| | 05:22 | But the fact is Sigma, which makes
this enormous 800 millimeter lens here,
| | 05:26 | makes very good lenses, as does Tamron.
| | 05:29 | So, you're going to want to check some
review sites and very often you'll find
| | 05:32 | that the third-party lenses deliver
equivalent quality for less price than the
| | 05:38 | camera manufacturer does.
| | 05:41 | Some other practical concerns: durability.
| | 05:44 | These, a lot of these are Canon lenses.
| | 05:46 | The ones with the red stripe,
these are the L-Series of lenses.
| | 05:49 | That's Canon's high-end
professional level glass. Very high quality.
| | 05:55 | Another nice thing about L-lenses is
they're built with exceptional weather sealing.
| | 06:02 | Just because it's raining,
it doesn't mean you shouldn't go out.
| | 06:04 | But you do want to be a little concerned
about how your camera might fare in foul weather.
| | 06:09 | These all lenses have a
rubber gasket right here.
| | 06:11 | So, when they go onto your lens,
they're really good, really well sealed.
| | 06:15 | They're also very, very sturdy.
| | 06:17 | They're going to be able to take a
little more damage than a less expensive,
| | 06:21 | more plasticky lens.
| | 06:24 | These white lenses of
Canon's are very distinctive.
| | 06:26 | And a lot of people think this is just
fashion because it shows that if you got
| | 06:29 | the white lens, you've got this
fancy expensive lens, which it does.
| | 06:32 | There's also a practical reason.
White absorbs a less heat and that has an
| | 06:36 | impact on the inside of the lens.
| | 06:37 | So, white versus black should not
be one of your considerations when
| | 06:42 | you're weighing lenses.
| | 06:43 | These are all factors that you're going
to want to consider and you are going to
| | 06:46 | have to balance all of them.
| | 06:47 | Once you've consider these issues, you'll
probably find yourself facing a few choices.
| | 06:51 | And at that time, you're going to zero in
on the particular parameters that you need.
| | 06:55 | In the end, of course it's
using the lens that matter.
| | 06:59 | So, don't get hung up on, boy,
| | 07:01 | this lens is really great and has all
these features and I really like it.
| | 07:04 | If you're not going to
use them, it's not worth it.
| | 07:05 | Find the lens that's right
for you, and then go out and start shooting.
| | Collapse this transcript |
| Lenses for crop sensor cameras| 00:01 | By now you should be well acquainted
with the idea that different cameras can
| | 00:05 | have different sized sensors.
| | 00:07 | But if you use an SLR with a cropped
sensor, that is, one whose sensor is
| | 00:12 | smaller than a piece of 35mm film, then
you have some additional lens options.
| | 00:17 | Take a look at this.
| | 00:18 | I have got here a Canon 5D, which
has a full frame sensor, and a Canon 7D,
| | 00:24 | which has a cropped sensor with a
crop factor of 1.6, just like we were
| | 00:28 | talking about earlier.
| | 00:29 | I have taken the lenses off so that you
can see inside to see the mirror chambers.
| | 00:33 | Now, we haven't talked about SLR
anatomy. You can learn about that in
| | 00:36 | the exposure course.
| | 00:37 | But inside this chamber, when I take the
lens off, there is mirror that reflects
| | 00:42 | light up into the viewfinder and you
can see very easily that the full frame
| | 00:48 | sensor has a much larger mirror
than the camera with the crop sensor.
| | 00:52 | That's because the sensor is so much larger
that it takes a bigger mirror to cover it up.
| | 00:57 | Now, what you can't see here from this
angle is that the mirror in this camera
| | 01:01 | in the 7D, the camera with a crop sensor,
the smaller mirror, is actually set a
| | 01:05 | little farther back in the
mirror chamber than this camera is.
| | 01:08 | What that means is I've got more space
here in front of the mirror than I do here.
| | 01:13 | Now to understand this next bit,
you need to know that if you can get a
| | 01:17 | lens closer to the sensor, you can build a
lens that is physically smaller and lighter.
| | 01:25 | So, now take a look at this.
| | 01:26 | I have two lenses here.
| | 01:30 | This lens will fit on either the 5D
with the full frame sensor or the 7D
| | 01:35 | with the crop sensor.
| | 01:36 | Now, look at this little bit right here.
| | 01:38 | That bit that's sticking up.
| | 01:39 | This is what goes into the mirror
chamber when the lens is mounted on the camera.
| | 01:44 | Now, I've got another lens here.
| | 01:46 | This lens is specifically for a Canon
camera with a crop sensor, like the 7D.
| | 01:52 | And if you look at this bit that's
sticking out, the part that goes inside the
| | 01:55 | mirror chamber, you can see there
is this extra little bit on top.
| | 01:59 | This lens will not work on the 5D.
| | 02:02 | There's not enough room in the 5D's
mirror chamber for this extra little bit.
| | 02:07 | What this means though, the advantage if
you have a crop sensor camera, like the
| | 02:10 | 7D or the Rebel or the 10-series Canon
camera, is that the back part of the lens
| | 02:16 | can actually be physically
closer to the image sensor.
| | 02:20 | And as I explained earlier, if you can
get the lens closer to the sensor,
| | 02:23 | you can make the lens physically smaller.
| | 02:26 | This is a Canon 18mm to 55mm lens.
| | 02:30 | To build an 18 to 55mm lens that
would work on the 5D with its full frame
| | 02:35 | sensor would require a bigger,
a physically larger lens than this.
| | 02:40 | So, this is one of the advantages of a
crop sensor camera, is that lenses can be
| | 02:44 | made smaller and lighter.
| | 02:46 | Now, Canon labels their lenses that
are designed specifically for smaller
| | 02:51 | cameras or smaller sensor
cameras with an S label.
| | 02:54 | So, I can see here this is an 18 to 55 EFS.
| | 03:00 | Nikon also makes a line of lenses
designed specifically for their crop sensor
| | 03:04 | cameras and those have a DX modifier.
| | 03:07 | Now, you might have another SLR like
an Olympus SLR, and there there's no
| | 03:11 | difference because Olympus
only makes crop sensor cameras.
| | 03:15 | So, all of their lenses will
work on all of their cameras.
| | 03:18 | What this means is if you've got a crop
sensor camera and you're going out lens
| | 03:21 | shopping, you want to be sure to
remember to look for the lenses that are
| | 03:27 | specifically for crop sensor cameras in
addition to the full range of full frame
| | 03:32 | sensor lenses, because the crop sensor
lenses are possibly going to be lighter
| | 03:36 | and smaller and less expensive.
| | 03:39 | Something else you should know with
Canon lenses, you may know about L lenses.
| | 03:42 | The L series of lenses is
Canon's high-end professional line of
| | 03:47 | lenses. That means expensive.
| | 03:50 | A lot of S lenses are actually L glass,
meaning you're doing an L quality lens,
| | 03:55 | but in a small package.
| | 03:56 | Canon has just made the decision that
they will not put both an L and S on a lens.
| | 04:01 | So, the crop sensor lenses can be
extremely high quality. Both Canon and Nikon
| | 04:07 | make very, very good crop sensor cameras.
| | 04:09 | They are worth looking at if you have
a crop sensor camera, because they are
| | 04:12 | going to be smaller and lighter.
| | 04:13 | The downside is if you ever upgrade to
a full frame camera, you are not going
| | 04:17 | to be able to take your lenses
with you, but that's what eBay is for.
| | 04:20 | In the meantime, it means your camera
bag can be much, much smaller and lighter.
| | Collapse this transcript |
| Image quality| 00:01 | After considering what kind of lens
you're looking for and what the options are
| | 00:04 | from various lens manufacturers, you're
ready to start looking at the specifics
| | 00:09 | of your individual candidates.
| | 00:11 | There is only one single feature that
should be your make-or-break kind of
| | 00:15 | deciding feature for a
lens and that's image quality.
| | 00:18 | No matter what extra features the lens
has, if it can't deliver a good image,
| | 00:22 | you should eliminate it
from your range of choices.
| | 00:26 | Evaluating image quality can be broken
down into just a number of simple kind of
| | 00:30 | steps and parameters.
| | 00:31 | And here are the things that
you want to consider. Sharpness.
| | 00:34 | Sharpness is a tricky thing because
there is no objective standard for
| | 00:37 | sharpness. In optical circles, they
often refer to sharpness as acceptable
| | 00:42 | sharpness and what's acceptable to you
is really all that matters. Contrast.
| | 00:47 | And I am going to relate this to color
also. Just how good does the lens deliver
| | 00:52 | rich colors and nice contrast with a lot of pop.
| | 00:55 | This again is a somewhat
ineffable indefinable quality.
| | 00:58 | You have just got to look at some
images and see what you like. Lens flare.
| | 01:02 | These are those weird circular
reflection patterns that you get if you point
| | 01:06 | the lens into a light.
| | 01:07 | Wide-angle lenses are far more
susceptible to flare than telephoto lenses.
| | 01:11 | And the way to check for this is to
put the lens on the front of a camera and
| | 01:15 | watch the edges as you move
the lens towards the light source.
| | 01:18 | See if you get any bad flare problems.
| | 01:20 | It can be difficult thing to really
force the lens into flaring, but if it
| | 01:23 | happens very easily, you know that
that lens probably has a flare problem.
| | 01:27 | Distortion are those weird spherical
geometric things that happen mostly with
| | 01:32 | wide-angle lenses, and we saw examples
of that before. That's where the corners
| | 01:36 | and the edges get all warpy.
Horizontal and vertical lines start to bend.
| | 01:41 | Spherical distortion like that is
certainly something you really want to check
| | 01:44 | for when you're looking at a prime lens,
but it's also true with zoom lenses.
| | 01:48 | If a zoom lens has a really wide angle
end to it, you want to test for distortion
| | 01:52 | and flare there also.
| | 01:53 | So, you are going to want to take your
zoom lens, zoom it out all the way, see
| | 01:56 | if you can point it at some
light to get it to flare.
| | 01:58 | Pan it around the room, watch the
corners, and see if you see distortion.
| | 02:02 | If a lens is not good enough to focus
all wavelengths of light to precisely the
| | 02:07 | same point, you get something
called chromatic aberration.
| | 02:09 | You may have seen this with the kit
lens that came with your camera because
| | 02:13 | they very often have these problems.
Where you will see it is shooting a
| | 02:16 | high contrast situation.
| | 02:17 | So maybe leaves up against a bright sky,
telephone wires up against the bright
| | 02:21 | sky, the line of a rooftop
up against the bright sky.
| | 02:24 | Rather than just a nice smooth edge,
you will have an edge with purple or
| | 02:28 | magenta, sometimes green
or cyan fringes around it.
| | 02:31 | That's because those wavelengths of
light are scattering, rather than being
| | 02:35 | focused to the same point.
| | 02:36 | You can fix that in your image editor,
but you really don't want to count
| | 02:40 | on your image editor to solve problems.
You wan to shoot good images in your camera.
| | 02:44 | It's difficult to test for that on
your own, but lens review sites will very
| | 02:47 | thoroughly test for and tell
you about chromatic aberration.
| | 02:51 | Boca, as we saw earlier, is the
softening that happens with--
| | 02:56 | lens softening in the background that
happens when a lens is open to its widest aperture.
| | 02:59 | So, if you are buying a really fast lens,
you want to evaluate the Boca, if you
| | 03:03 | are the type of person who's
picky about that sort of thing.
| | 03:05 | If you're buying a fast lens, you're
probably spending a lot of money so you
| | 03:08 | might as well be picky about Boca.
| | 03:10 | Just take a look at it and see if
you like the shape of really bright
| | 03:13 | highlights in the background.
| | 03:14 | If you like them round, if you like
them more polygonal, that's going to be the
| | 03:19 | difference in Boca that may
help make your buying decision.
| | 03:22 | So how you evaluate all this stuff?
| | 03:25 | Obviously reading lens reviews is one thing.
| | 03:27 | The web is full of lens review
sites and camera review sites.
| | 03:31 | A lot of those sites will let you download
full-res images shot with particular lenses.
| | 03:35 | That's a nice way to get images into your
image editor where you can look at them up close.
| | 03:39 | Best thing to do though is, if you can,
rent the lens that you're considering or
| | 03:43 | even a couple lenses that you are considering.
| | 03:44 | That gives you a chance to take them out
and shoot with them on your own, really
| | 03:48 | take them for a test drive.
| | 03:49 | Online rental places like
borrowlenses.com are great for that.
| | 03:53 | Your local camera store might have a
rental house attached to it that will let
| | 03:57 | you get a lens out the door and shoot with it.
| | 03:59 | Ultimately, the thing to remember though is,
image quality, image quality, image quality.
| | 04:02 | That's what should define your buying
decision and that's what you want to
| | 04:06 | consider very carefully before
you make your final purchase.
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| Lens features| 00:01 | In addition to quality differences, some
lenses will have more features than others.
| | 00:05 | Now quality should be your main
selection benchmark, but you want to pay
| | 00:08 | attention to other features as well.
| | 00:11 | I've got a couple of zoom lenses here
and there is an important difference in
| | 00:14 | the way that they zoom.
| | 00:15 | This lens has an internal zooming mechanism.
| | 00:17 | When I turn the zoom ring, you don't
see anything happening outside the lens.
| | 00:21 | If I look inside though, I see all sorts
of lens elements and things moving around.
| | 00:25 | This lens has an external zoom mechanism.
| | 00:28 | When I turn the zoom ring, the lens
gets physically longer and shorter.
| | 00:31 | Now you now think that is much of a big
deal and it may not be, but if you spend
| | 00:36 | the lot of time in foul weather and
rough environments, an external zooming
| | 00:41 | mechanism like this could begin to wear
out quicker, because dust and stuff can
| | 00:45 | get on here and actually be
carried down inside the lens mechanism.
| | 00:49 | So an internal mechanism is
definitely more durable and long-lasting than
| | 00:54 | an external mechanism.
| | 00:55 | These days most zoom lenses, even
inexpensive zoom lenses, maybe even the kit
| | 00:59 | lens that came with your zoom,
come with stabilization features.
| | 01:03 | Optical image stabilization
is an incredible technology.
| | 01:06 | The way it works is the very
last element in the lens that can be
| | 01:09 | reshaped on-the-fly.
| | 01:11 | So as you jitter the camera the lens can
correct for that and stabilize your image.
| | 01:15 | There is no substitute for a tripod.
If you're trying to shoot from moving car,
| | 01:19 | stabilization is not going to do you
any good, but it will help counteract some
| | 01:23 | of the handheld shake that you might
experience and it's particularly useful for
| | 01:26 | very long telephoto lenses.
| | 01:28 | On this lens, I have here the
stabilizer. I can turn it off and on.
| | 01:33 | There are times when you want to turn
off stabilization if your battery is
| | 01:36 | running low especially, but also if
you're working from a tripod, it's a good
| | 01:38 | idea to turn off stabilization.
| | 01:41 | I also have two modes of stabilization.
| | 01:43 | On this particular lens, I can have full
stabilization or I can tell it to only
| | 01:47 | stabilize on one axis,
which is good when I'm panning.
| | 01:51 | Stabilizers are rated in terms of stops.
| | 01:54 | So a lens might have a 3-stop stabilizer.
| | 01:57 | What that means is if I
calculated my handheld shutter speed,
| | 02:02 | while using the handheld shutter speed
| | 02:04 | rule you can learn about in
Foundations of Photography: Exposure,
| | 02:07 | Once I've calculated that shutter
speed if I have a 3 stops stabilizer I can
| | 02:11 | actually shoot 3 full stops underneath
that without having to worry about camera
| | 02:15 | shake, at least that's what the
camera manufacture will tell you.
| | 02:18 | Whether that's true or not kind of
depends on how steady you are and how good
| | 02:21 | their stabilization actually is.
| | 02:23 | Stabilization is a great feature to look for.
| | 02:26 | And if you're trying to decide between
lens of equivalent qualities and one has
| | 02:30 | stabilization and the other doesn't and
you can afford both, you definitely want
| | 02:33 | to go with the stabilization.
| | 02:35 | Autofocus, all of these lenses are auto-focus.
| | 02:38 | It can be switched on and off.
Again on this lens I can turn
| | 02:41 | a little switch here that says
AF/MF. I've got the same thing over here.
| | 02:47 | You might want to consider autofocus speed.
| | 02:49 | If you're a sports or a nature shooter,
you want a lens that can focus very quickly.
| | 02:53 | Autofocus noise is can also be an issue.
| | 02:55 | If you're an event shooter you don't
want a zzr-zzr-zzr sound interrupting a wedding or
| | 02:59 | something like that. That's
something to consider when you're shopping.
| | 03:03 | You might have spent extra money on a
camera that claims to be weatherproof, or
| | 03:06 | not weatherproof but a little more
weather resistant than another camera.
| | 03:10 | That weatherproofing is only as
good as your connection to the lens.
| | 03:14 | So if you are again shooting in rough
environments and you want to sure that the
| | 03:18 | weatherproofing on your camera holds up,
you want to be certain to get a lens
| | 03:21 | that has weather sealing rings
around its mounting edge here.
| | 03:26 | And it's just a little
rubber gasket there basically.
| | 03:30 | Lenses also have filter mounts.
| | 03:33 | So there is threads right
here for attaching filters.
| | 03:35 | You can see on this lens,
we've got a UV or Haze filter.
| | 03:39 | These are worth putting on all of your lenses.
| | 03:40 | They don't adjust the quality of your image
at all, but they will protect your lenses.
| | 03:44 | We're going to talk a lot about filters later.
| | 03:47 | All filters have a thread size.
| | 03:49 | If you've already got filters of a
particular size, you might be interested in
| | 03:52 | finding out whether the lens you're
considering can use those filters. Lens markings.
| | 03:59 | This is kind of a touchy subject for
me, because lenses just don't have the
| | 04:02 | markings that they used to!
| | 04:03 | You can see here that
I've got focus markings here.
| | 04:06 | These tell me where I'm focused.
| | 04:09 | It's measured in feet and meters and so
I can see right now I measure to 15 feet
| | 04:13 | or roughly 5 meters it's saying.
| | 04:16 | If you're lucky or if you're
shopping for older lenses, you might find
| | 04:19 | lenses that have aperture gauges and
depth of field gauges on them and those were
| | 04:23 | really, really handy.
| | 04:24 | Particularly if you like to shoot
manually. Most lenses these days don't have them.
| | 04:28 | So if you're coming-- if you're an old-
school photographer and you're looking for that,
| | 04:31 | don't expect to find it.
| | 04:32 | Another thing you really see that
differentiates one lens from another are coatings.
| | 04:36 | You'll see that mention and I
won't go into much detail about it.
| | 04:39 | They might have some
patented name about their coatings.
| | 04:42 | If I tilt the lens at an angle, you may
be able to see strange colors across it
| | 04:46 | or interesting reflections or something.
| | 04:48 | Those are because the lenses have been coated.
| | 04:50 | Lens coatings are designed to reduce glare.
| | 04:53 | As light goes into the lens, it might
bounce around inside. That can lead to
| | 04:57 | those circular lens flares that you
see, or an overall loss of contrast, or
| | 05:01 | diffusion of the contrast.
Coatings can help prevent that.
| | 05:05 | As you're reading reviews you might see
where expert reviewers are actually talking
| | 05:09 | about the quality of a coatings and
how good of job they do and that's definitely
| | 05:12 | something to consider when shopping for a lens.
| | 05:14 | I got these lens shades over here.
| | 05:17 | A lot of lenses, particularly high-end
lenses and especially wide-angle lenses,
| | 05:22 | will ship with a lens shade.
| | 05:23 | This is a 16 to 35 millimeter lens. It comes with
this shade that I can just pop on the front here.
| | 05:29 | And the reason that I really want to a
lens shade with a wide-angle lens is that
| | 05:33 | wide-angle lenses are
especially susceptible to flare.
| | 05:37 | If I'm shooting into light, light
coming at an extreme angle can again bounce
| | 05:41 | around inside the lens and give
me all sorts of awful artifacts.
| | 05:44 | Having this filter on here you can see I've got
stuff that bonk-- you know, that keeps the light
| | 05:48 | from getting into the lenses way.
| | 05:50 | So a nice lens shade is something to
consider when you're shopping around.
| | 05:54 | Finally lens mounts.
| | 05:55 | If you're shopping for -- if lens
shades are very important for wide-angle
| | 05:59 | lenses, lens mounts are very
important for really long telephoto lenses.
| | 06:03 | This thing is heavy.
| | 06:04 | It's pretty much solid metal on the
outside and fortunately, it's got a mount
| | 06:09 | for a tripod on the lens.
| | 06:11 | If I put this thing on my camera and
put my camera on a tripod, I'm going to be
| | 06:15 | putting a tremendous amount of
strain on the mount of the camera.
| | 06:19 | By having a tripod mount on my larger
lens, I can give my camera a break and have
| | 06:23 | a better balance when I'm
trying to pan and tilt around.
| | 06:27 | So those are a few of the really
critical features that you need to consider
| | 06:30 | when you're shopping for a lens, but
again remember ultimately, it always comes
| | 06:34 | down to image quality.
| | 06:35 | You want the lens that's going to
deliver the best quality. If you can get some
| | 06:39 | of these cool extra
features that's a definite plus.
| | Collapse this transcript |
| Size and weight| 00:02 | In addition to the technical
considerations we've been talking about, there
| | 00:06 | are a number of practical concerns
that you need to weigh when you're
| | 00:09 | considering a new lens.
| | 00:10 | First of all what does it cost?
| | 00:12 | Second, how big is it?
| | 00:14 | Will it fit in your bag?
| | 00:15 | Is it going to break your neck if you
carry it around on your shoulder all day long?
| | 00:20 | But, maybe one of the most important
decisions is how does this lens you're
| | 00:24 | considering fit into the collection
that you already have? Is it redundant?
| | 00:28 | Does it add something new?
| | 00:30 | What kind of assortment of lenses do you need
for the type of shooting that you do everyday?
| | 00:35 | Lens selection gets easier as you
become more experienced and learn more about
| | 00:39 | what types of images that you like to shoot.
| | 00:42 | Typically though, you're
going to want a walk-around lens.
| | 00:44 | That is, a lens that offers a good
focal length or range of focal lengths
| | 00:49 | for everyday shooting.
| | 00:50 | I keep a 24-105 millimeter
on my camera for everyday use.
| | 00:54 | That gives me a range from a nice
wide angle to a slightly telephoto.
| | 00:58 | Now, I'm not going to do any wildlife
shooting with a 105 millimeter lens, but
| | 01:01 | the fact is I don't encounter a lot
of wildlife in my day-to-day shooting.
| | 01:05 | If I'm heading out for a day of shooting,
I'll also carry a 16-35 since I tend
| | 01:10 | to err more on the wide angle side of
things for the types of images that I
| | 01:14 | shoot than I do on the telephoto.
| | 01:16 | Because it's nice to have a really fast
lens, I also carry a 50 millimeter 1.2.
| | 01:21 | That gives me the option for shooting
in low light and shooting with really
| | 01:25 | shallow depth of field.
| | 01:28 | When you're considering the size and
weight of a particular lens, remember that
| | 01:31 | it's not just the size and weight of
this one lens that matters, but of all of
| | 01:36 | the lenses that you
might carry at the same time.
| | 01:38 | While this one slightly heavyish lens
might be manageable on its own, what about
| | 01:42 | when you stick it in a bag with two or
three other slightly heavyish lenses?
| | 01:46 | This is the bag that I use
for my everyday shooting.
| | 01:49 | It's not huge, but it's big enough to
hold these three lenses that I like to
| | 01:53 | have with me for just my normal walk-
around shooting. I can get these three lenses
| | 01:58 | and my fairly large full frame
sensor camera all in this bag.
| | 02:02 | I've also got a couple of extra
pockets here which is handy for carrying
| | 02:06 | additional memory cards
which can be very important.
| | 02:08 | Let's see. I've also got a white
balance card in here for ensuring that I get
| | 02:13 | good white balance and I keep a
remote control because a lot of times I'm
| | 02:17 | shooting in low light on a tripod and
want to be able to attach a remote control
| | 02:21 | to keep from having to shake
my camera while I'm shooting.
| | 02:24 | All that goes on here
and this is a shoulder bag.
| | 02:26 | I can sling it over one shoulder
or put it all the way over my head.
| | 02:30 | I prefer this to a backpack because
a lot of times I'm shooting in the
| | 02:33 | backcountry and I'm hiking, and I
want to be able to also carry either a
| | 02:37 | backpack with food and supplies in
it or a CamelBak with some water in it,
| | 02:41 | something like that.
| | 02:42 | So this allows me to carry a
couple of bags at one time.
| | 02:45 | What I also like about this is I can
get to it without having to take it off.
| | 02:48 | I've got full access to everything
right here, unlike a backpack which I have to
| | 02:52 | take off and turn it on and
open up and pull stuff out.
| | 02:54 | This is a very practical
day-to-day shooting bag.
| | 02:59 | If I'm going on a trip somewhere though, I'm
probably taking more lenses than just these.
| | 03:03 | These are the lenses that I
use for my everyday stuff.
| | 03:05 | But let's say I'm going somewhere
where I know this is going to work for most days,
| | 03:09 | but on some days maybe I'm going
on safari, so I want to be sure that I've
| | 03:13 | got a long telephoto lens with me.
| | 03:15 | Maybe I'm going to a friend's
wedding and I know I'm going to be shooting
| | 03:18 | indoors a lot, so I want to
take some flashes with me.
| | 03:21 | That's a lot of stuff to
carry, too much to go in here.
| | 03:23 | So sometimes you need a separate bag just
to get all your gear to where you're going.
| | 03:28 | Then maybe you cherry-pick the gear you
want for that particular day and put it
| | 03:32 | in your carry around shooting bag.
| | 03:35 | This is what we have here.
| | 03:35 | This is a nice big photo backpack that I can
take with me and I can put a lot of stuff in here.
| | 03:40 | If you open it up, you'll see that
this is actually a camera specific bag.
| | 03:44 | This is not just a big backpack.
| | 03:46 | This is a bag that is
designed for carrying camera gear.
| | 03:49 | I've got movable panels in here
that I can use to custom fit my exact
| | 03:54 | selection of stuff.
| | 03:55 | So I've got a body in here, I've got a
couple of big lenses, I've got this nice
| | 03:58 | long telephoto, a couple of primes, a
flash. I've also got lots of compartments
| | 04:03 | here for carrying memory cards, white
balance cards, remote controls, those can
| | 04:06 | all zip into there, and
I've got some external pockets.
| | 04:11 | If I'm going somewhere where weather might
be a concern, not so much water but dust.
| | 04:16 | If I am going to go somewhere very
sandy, I want to look at a bag that's
| | 04:19 | got sealed zippers.
| | 04:22 | If I need any waterproofing, that's about
an entirely different category of packing.
| | 04:27 | That's not so much a day-to-day shooting thing.
| | 04:29 | This is a backpack.
| | 04:31 | Because it's so big,
| | 04:32 | it's got a hit belt, which is nice
because that will put some of the weight on
| | 04:35 | my hips and take it off of my shoulders.
| | 04:38 | However, if I'm going on a long flight
where I'm making a lot of connections,
| | 04:41 | carrying this on my back all day long
is going to be pretty tired, particularly
| | 04:44 | if it's big airports that I'm having to
run from terminal to terminal through.
| | 04:49 | That's where a bag like this scores.
| | 04:50 | It can hold as much stuff as that bag,
but it has the benefit of these two
| | 04:55 | wheels back here which is very nice.
| | 04:56 | It's like a rolling suitcase.
| | 04:58 | I can pop this up, roll it around,
but I've also got these backpack straps.
| | 05:01 | So if I've got to go up an escalator
or run to catch a cab or something, I can
| | 05:05 | just throw it on my back and take off.
| | 05:08 | Both of these bags I packed with the
intention that I'm going to carry them on.
| | 05:13 | I don't want to check this kind of
photo gear, particularly in a soft bag,
| | 05:19 | and especially on an international
flight where a lot of times things from
| | 05:22 | checked bags can tend to disappear.
| | 05:24 | So you want to before you go ensure that
your bag is the right size to go in, in
| | 05:28 | an overhead compartment.
More important possibly is weight.
| | 05:32 | International air flights especially,
going through international airports,
| | 05:35 | they're going to be very picky about weight.
| | 05:37 | If this is just a pound or two over,
they're going to ask you to take something
| | 05:40 | out of it, and suddenly you're
pulling your $1000 lens out of your bag and
| | 05:44 | wondering what to do with it.
| | 05:46 | So find just a cloth shopping bag or
something that you could stuff in one of
| | 05:48 | the outside compartments.
| | 05:50 | You can pull that out, put your extra
stuff in there, and at least you've got a
| | 05:52 | way to carry it around until
you can get it back in the bag.
| | 05:57 | Remember too that you are not just
carrying camera gear and this goes into your
| | 06:00 | gear selection considerations.
| | 06:02 | You're probably possibly
going to take a computer with you.
| | 06:05 | That might require some extra hard-
drives, a computer power supply, and
| | 06:08 | maybe extra batteries.
| | 06:09 | Of course you're also carrying camera
batteries, camera chargers, all that stuff adds up.
| | 06:13 | So that goes into possibly your lens selection.
| | 06:16 | You might think, boy,
| | 06:17 | I'd love to have that 15 millimeter
fisheye with me, but realistically I'm not
| | 06:21 | going to use it that much and it's
better for me to have more batteries.
| | 06:24 | So it's a constant kind of
multidimensional problem of what gear do you take
| | 06:28 | and how do you pack it.
| | Collapse this transcript |
| Lens notes for Micro Four Thirds| 00:01 | SLRs are great for their exceptional image
quality, thanks to their very large sensors,
| | 00:06 | the ability to interchange lenses
for more shooting flexibility, their
| | 00:11 | professional level of controls, their
exceptional viewfinders. All in all,
| | 00:15 | if you're serious about taking a good
picture an SLR is very often the way to go.
| | 00:19 | The problem is very often you don't
want to take your SLR with you just because
| | 00:22 | it's so big. It doesn't fit in a pocket.
Maybe it's going to be drag if you're
| | 00:26 | carrying other things.
| | 00:27 | That's what we have point-and-shoot cameras.
| | 00:29 | Smaller sensors that make for a smaller
camera but still today's point-and-shoot
| | 00:33 | cameras can deliver excellent image quality.
| | 00:35 | They're really small and easy
to work with, very pocketable.
| | 00:37 | But they're lack of certain
flexibility. They can't change lenses.
| | 00:40 | You don't have a real viewfinder.
| | 00:42 | A few years ago some camera
manufacturers got together, recognized this problem
| | 00:46 | and created something called the Four
Thirds Standard, which specified a image
| | 00:52 | sensor that's larger than a point-and-
shoot camera. And the reason we care about
| | 00:55 | sensor sizes that as your image
sensor gets larger, you gain the ability to
| | 00:59 | shoot with more shallow depth of field
and you lower the amount of noise, those
| | 01:02 | little speckly colored
patterns that can appear in an image.
| | 01:06 | So you'll get a larger image sensor
with a four thirds camera and you'll
| | 01:09 | get removable lenses.
| | 01:11 | A little bit after that, they came up
with the Micro Four Thirds specification,
| | 01:15 | which is what I have here.
| | 01:16 | this is a micro four thirds camera.
| | 01:18 | So it's smaller than an SLR.
| | 01:20 | It's a little bit bigger than a point-and-shoot.
| | 01:22 | It really does sit between these two cameras.
| | 01:25 | What's nice about it is it is still
small enough that I can put in a coat
| | 01:28 | pocket, or even if I just have it hanging
up my shoulder it doesn't weigh very much.
| | 01:31 | It's got an image sensor that's
larger than a point-and-shoot, not quite
| | 01:34 | as large as an SLR.
| | 01:36 | So I can still have depth of field
control, I still get really low noise and I
| | 01:40 | get removable lenses.
| | 01:41 | So I get a lot of flexibility of an SLR and a
lot of the convenience of a point-and-shoot.
| | 01:47 | The downside to a micro four thirds
camera is that the specification dictates
| | 01:52 | that the lens has to be
pretty close to the image sensor.
| | 01:55 | So close that there's no room inside
for a mirror. That means I can't have an
| | 01:59 | actual optical viewfinder of
high-quality like I can with an SLR.
| | 02:03 | So it kind of a small price to pay if
you're tired of carrying a heavy camera.
| | 02:07 | So, Panasonic, Olympus, a couple of other
vendors are all signed on to the Micro
| | 02:12 | Four Third standards and making
micro four thirds cameras and lenses. Because it's
| | 02:16 | a standard I can change
lenses from any micro four thirds camera.
| | 02:20 | For example, what I have on here
right now is a 20mm Panasonic lens with a
| | 02:25 | maximum aperture depth 1.7.
| | 02:28 | Micro four thirds cameras all have a
multiplication factor of 2x, so this ends
| | 02:32 | up being the equipped on 40mm lens on
a 35 mm camera, and so that makes this
| | 02:37 | almost a normal lens.
| | 02:39 | With an aperture depth of 1.7. So this
is a really nice walk-around fast lens.
| | 02:43 | As you can see it is very thin.
| | 02:44 | It is referred to as a pancake lens.
| | 02:47 | But I got another fine selection of
lenses from a couple of different vendors.
| | 02:51 | I actually also like this Olympus lens.
This is not a Panasonic lens but it
| | 02:55 | still fits on my Panasonic GF-1 here
just fine, because again this is the Micro
| | 03:01 | Four Thirds standard. This is the A-1.4
to 42, which makes it a 24 to 84 mm lens.
| | 03:07 | So at the time that we're shooting,
there's a nice assortment of micro dour
| | 03:12 | thirds lenses out there. Here is a 7 to 14
that gives me the equivalent of a 14 to 28.
| | 03:18 | One thing I hope you're noticing about
these lenses, this is a very wide angle
| | 03:21 | lens and it's pretty fast.
| | 03:24 | It's an F4 all the way across.
| | 03:26 | So a 14 to 28mm equivalent
lens and it's only this big.
| | 03:31 | Again it's not just the cameras that
are small, but the lenses themselves are small.
| | 03:34 | I can carry a whole kit of
lenses in very little space.
| | 03:37 | But another really cool thing about
micro four thirds cameras is not long after
| | 03:41 | they were released, people started
making gobs of adapters for attaching just
| | 03:45 | about any other type of lens that you
can imagine. What I have here is a Canon
| | 03:49 | adapter. This lets me attached Canon
lenses to my micro four thirds camera.
| | 03:54 | It's the bayonet mount adapter, just
like all these lenses. This type of mount
| | 03:57 | where I don't have to completely
unscrew the lens, but I can just turn it a
| | 04:00 | little bit. That's called a bayonet mount.
| | 04:02 | So I can just pop this on my camera
and now I got a Canon mount right there.
| | 04:06 | Here is the Canon 15mm fisheye and
now it just pops right onto my micro four thirds camera.
| | 04:12 | The same adapter would work on any other
micro four thirds camera. Some caveats though.
| | 04:18 | These days aperture control and auto-
focus is all managed by electronics that
| | 04:23 | pass electronic connections
from the camera to the lens.
| | 04:25 | This adapter does not pass any of
that stuff, so my lenses are going to
| | 04:28 | completely manual now.
| | 04:29 | There is no auto-focus, nor is there
any aperture control. The lens is always
| | 04:33 | stuck at its widest aperture.
| | 04:35 | So this is fortunately an F2.8.
| | 04:37 | So I have to put my camera into
manual mode. I have no aperture control.
| | 04:41 | I can just play with the shutter
speed until I get a good exposure.
| | 04:43 | Something else to bear in mind. This
is a 15mm fisheye, which means lots and
| | 04:48 | lots of wide-angle distortion.
| | 04:49 | But because of that 2x multiplication
factor, the 2x crop factor, I'm only taking
| | 04:54 | the very center of the lens and the
part that I'm taking is not that distorted.
| | 04:58 | So I'm not getting a
great fisheye effect on this.
| | 05:00 | Still, I'm getting a pretty wide angle
lens and if may be you buy a micro four
| | 05:04 | thirds camera and you just buy the
kit lens, but you got a nice wide-angle
| | 05:07 | already for your SLR and it's not too big,
| | 05:09 | a little $25 adapter like this
can immediately get you another lens.
| | 05:14 | A nice thing about that
multiplication factor though, one thing about this
| | 05:17 | adapter-- this particular one
it's hard to get off of lenses.
| | 05:21 | One nice thing about that
multiplication factor though is when you're working with--
| | 05:24 | when you want a long focal length lens,
| | 05:28 | if you're really into shooting telephoto
having that 2x multiplier can be a good
| | 05:33 | thing for your other lenses.
| | 05:35 | For example, let's say I really wanted
to go shoot something that was far away
| | 05:38 | and I thought, "Oh, I know, I've got
just the thing in the back of my closet.
| | 05:42 | That old Sigma 100mm." I can now
just pop my camera right onto this.
| | 05:47 | Noticed I don't say pop the lens onto
the camera, because when you're working
| | 05:50 | with the lens of this size, it's more
that you put the camera on the lens not
| | 05:53 | the lens on the camera.
| | 05:55 | But nevertheless, though it's a little
ridiculous, I now have an 800mm lens on my
| | 06:00 | tiny little micro four thirds camera.
| | 06:02 | 2x multiplier means this is actually
the equivalent of a 1600mm lens, which is
| | 06:08 | great, but I had some really
serious surveillance in mind.
| | 06:10 | So now I might add a 2x multiplier.
That gets me up to a 3200mm lens.
| | 06:15 | That would go around in here.
| | 06:16 | Oh and why not just stack that
1.4x multiplier on top of it?
| | 06:19 | This would make this a 4480mm equivalent lens.
| | 06:24 | That's said, I should point out that
this is just about impossible to use on
| | 06:28 | this camera, because you don't have auto-focus,
| | 06:31 | it's very hard to hold it steady, and as
you add those teleconverters you lose f-stops.
| | 06:35 | Anyway these adapters are great and
you can get them for all sorts of things.
| | 06:38 | What's cool as people starting to adapt
not just camera lenses but film camera
| | 06:43 | lenses. If you have old Bolex 16mm
lenses, you can put those on here and those
| | 06:47 | are often very, very, very fast.
| | 06:49 | If you have a collection of nice old
Leica lenses, those are already very small
| | 06:53 | and fit on this kind of camera very, very well.
| | 06:56 | So if you've been frustrated by the
size of your SLR for certain occasions but
| | 07:00 | you don't want to give up a certain
level of flexibility and quality, definitely
| | 07:03 | check into micro four thirds cameras.?
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| Specialty lenses| 00:01 | So far we've mostly been looking at
fairly everyday lenses, but there are lots
| | 00:04 | of other optical gizmos that you can attach
to your camera to achieve all sorts of effects.
| | 00:08 | You can get strange effects, or stylized
effects, or even some practical effects.
| | 00:13 | You're already seen a fisheye lens and
how it gives you a very wide and very
| | 00:17 | distorted view of a scene. On the more
practical end of the spectrum are macro
| | 00:21 | lenses, which allow you to
shoot extreme close-ups of objects.
| | 00:25 | Technically what makes a macro a
macro lens is that there is a one-to-one
| | 00:29 | relationship between the size of the
object that you're shooting and the size of
| | 00:33 | the image that gets captured.
| | 00:35 | I'm going to skip all the math bit and
we'll just say that when you shoot with a
| | 00:38 | macro lens you can shoot close-ups
and get perspectives that you just can't
| | 00:42 | shoot with non-macro lenses.
| | 00:44 | Like other lenses macro lenses
come in a variety of focal lengths.
| | 00:47 | This is a 100mm macro, but you might
also see 60 and 50 millimeter macro lenses.
| | 00:53 | Those shorter macro lenses are
lighter and they're less expensive, but they
| | 00:57 | require you to get much closer to
your subject than a nice long macro like
| | 01:00 | this 100 millimeter.
| | 01:01 | So if you're serious about macro
photography you want to get the longest macro
| | 01:05 | lens that you can afford just for
the sake of shooting flexibility.
| | 01:09 | Now there are some zoom lenses out
there that claim to have a macro feature
| | 01:13 | built-in, but be very careful when
considering these lenses. If they can't achieve
| | 01:16 | a one-to-one magnification level
then they're not true macro lenses.
| | 01:21 | Extension tubes are
another budget macro alternative.
| | 01:25 | An extension tube doesn't
actually have any glass of.
| | 01:28 | It sits between your camera and your
lens and it serves to get the sensor
| | 01:31 | farther from the lens.
| | 01:33 | So it just attaches to the
back the way a lens would.
| | 01:36 | Different manufacturers make different
sized tubes and extension tubes will only
| | 01:40 | be compatible with lenses
up to a certain focal length.
| | 01:44 | Extension tubes usually won't get you to
a full one-to-one macro capability, but
| | 01:48 | they will come close and they're
not as expensive as a macro lens.
| | 01:51 | Now the downside to extension tubes
is that you have to get closer to your
| | 01:56 | subject than you would with a macro
lens and sometimes you can't actually get
| | 01:59 | close enough to focus.
| | 02:01 | Some people confuse extension tubes
with a tele-extender or teleconverter like
| | 02:07 | this one, but they're very different.
| | 02:09 | A tele-extender increases the
focal length of the lens and it's an
| | 02:13 | actual optical device.
| | 02:14 | You can see here that there is
actual glass in the extender. There is a
| | 02:17 | little lens element in there.
| | 02:19 | This particular extender is a 2x.
| | 02:21 | It doubles the focal
length of any lens I put it on.
| | 02:24 | So if I put it on my 400mm lens
here, then I have an 800mm lens.
| | 02:30 | As you can see tele-extenders, sometimes
called teleconverters, are very light and
| | 02:35 | they're very reasonably priced.
| | 02:36 | So you might think why would I buy an
expensive 400mm lens rather than a 200mm
| | 02:41 | lens and a tele-extender?
| | 02:43 | Well depending on your needs that might
not be a bad idea, but you should know
| | 02:47 | that there is no such thing as
a free extra 200 millimeters.
| | 02:51 | Teleconverters cost you some light.
In the case of this 2x converter,
| | 02:54 | it's a whopping two stops of light.
| | 02:56 | So where this 400mm lens is normally an
F5.6, with this converter it becomes an F11.
| | 03:04 | You'll also take a quality hit with a
converter. It's basically a magnifying glass that
| | 03:07 | you're sticking on the back of the lens.
| | 03:09 | So while it magnifies the size of the
image it also magnifies any flaws or
| | 03:13 | aberrations. You'll definitely notice a
sharpness penalty with the converter.
| | 03:17 | Depending on the lens you're using, you
may lose autofocus capabilities or your
| | 03:21 | autofocus maybe greatly slowed.
| | 03:24 | Here is another teleconverter. Rather
than 2x it only gives you 1.4x on your
| | 03:29 | focal length, but it also
only costs you one stop.
| | 03:32 | So you can eek out a little more focal
length without slowing the lens down too much.
| | 03:37 | This is a tilt-shift lens.
| | 03:40 | Now, the way this works is as I turn
these knobs, I can move the front and rear
| | 03:47 | elements of the lens independently.
| | 03:49 | Tilt-shift lenses have a number of
uses, but they're most commonly used for
| | 03:53 | architectural photography.
| | 03:55 | Look at this building. Because I was
looking up at it from ground level I'm
| | 03:58 | getting perspective distortion.
| | 04:00 | It's no longer kind of perfectly squared off.
| | 04:03 | It's receding into the sky.
| | 04:05 | With a tilt-shift lens, I can correct for
that perspective to square up the building.
| | 04:10 | Here is another a fairly unusual
thing you can put on your lens. This is a
| | 04:14 | lensbaby and it may look like some kind
of orthopedic device of some kind, but
| | 04:19 | what it actually is, is there is a lens
element back here and there is another
| | 04:22 | one up here and there is a bellows in
the middle and I can turn these kind of
| | 04:26 | torturous looking thumbscrew things
and that will shift the bellows so that I
| | 04:32 | now have a crooked lens.
| | 04:35 | What this lets me do is pick a
point of focus somewhere in my image and
| | 04:39 | then smear everything in the image out from
that point of focus, as you can see in this image.
| | 04:45 | Those are just a few of the options
that you might find for your camera.
| | 04:48 | There are other things you can stick
on the front of your camera such as a
| | 04:51 | pinhole lens for shooting digital
pinhole photographs, Holga lenses for getting
| | 04:55 | a grungy toy look, telescope adapters
for sticking your camera on the end of a
| | 04:59 | telescope, and a lot of other things.
| | 05:01 | If you're interested in a particular
type of photography, a little Googling
| | 05:04 | around should lead you to resources
and product reviews on specific hardware.
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| Where to buy| 00:01 | Eventually after comparing and
contrasting, weighing this against that, reading
| | 00:06 | gobs of online reviews and figuring out
what you can sell off on eBay, you might
| | 00:10 | finally be ready to buy a
lens. So where should you buy?
| | 00:14 | Of course looking online is probably
your first instinct and there are a lot of
| | 00:17 | good reputable sources for
lenses and cameras online.
| | 00:20 | So your first task will
simply be to compare prices.
| | 00:22 | Amazon usually stocks everything we
covered here and they're almost always
| | 00:25 | competitive on price.
| | 00:27 | Right now most of Amazon's camera
sales are handled by Adorama in New York.
| | 00:31 | B&H Photo also in New York has a
comprehensive selection and is also very
| | 00:35 | competitive on price, and if you
happen to be in Manhattan, stop by. B&H is
| | 00:39 | always fun and it's a great
chance to see stuff in person.
| | 00:42 | Calumet Photo is also a very
good source for camera gear.
| | 00:46 | In addition to their online presence
they had stores in many major cities around
| | 00:49 | the country. buydig.com is another good
option, or you may already have an online
| | 00:54 | vendor that you like.
| | 00:56 | If you see a price online that just
seems too good to be true, have no doubt
| | 01:00 | that it most certainly is.
| | 01:01 | In a lot of cases disreputable
online retailers will advertise a really hot
| | 01:06 | product at a low price but when you
call to order it they might try to push
| | 01:11 | you on a camera accessory. Get a bag or
something for the low-low price of $500 or something.
| | 01:17 | When you say you're not interested
they'll your order anyway, but they never
| | 01:19 | charge you or ship the camera. Worse
they won't tell you that that they're not
| | 01:23 | shipping the camera.
| | 01:24 | At other times the camera with a very
low price might be a gray market camera,
| | 01:28 | which means it won't be
covered by an actual warranty.
| | 01:31 | So while shopping online is very
compelling for the price savings, if you have a
| | 01:35 | local camera dealer it's
really worth checking them out.
| | 01:38 | Sure, they may night be able to
compete with online retailer for price, but
| | 01:41 | though sell you a lot more than just a lens.
| | 01:43 | Having a dealer that you can develop a
relationship with will not only help you
| | 01:48 | with your immediate purchase but it'll
provide a lot of additional support and
| | 01:51 | aid in the future, and for sure don't
go to a local store to look at piece of
| | 01:55 | gear in person and then go
order it online. That's just tacky.
| | 01:59 | Another great option is rental.
| | 02:01 | There might be a local rental house in
your area but renting online is also a
| | 02:05 | great option. borrowlenses.com has a
great selection, fantastic prices, great
| | 02:10 | service, lens rental is great for
those less frequent lens applications.
| | 02:14 | So, say, I don't know, maybe you need
to go shoot your kid's soccer game or
| | 02:19 | something, but you don't want to invest
in a long lens that you're not going to
| | 02:22 | use after soccer season is over.
| | 02:24 | Or maybe you can't afford to a really
fast lens, but you're going to wedding
| | 02:28 | that will take place at night.
| | 02:29 | A weekend rental of a nice 1.2
85mm will help you get shot that you
| | 02:33 | might otherwise miss.
| | 02:34 | Lens rental is also a great way to
audition lenses before you purchase.
| | 02:38 | So, if you're not absolutely certain
about a particular lens or you'd like to
| | 02:41 | maybe compare some lenses,
rent them and see what you like.
| | 02:45 | It's a great way to check out a lens
before you actually spend any money.
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| Lens caps| 00:01 | It's beautiful day out here today
and so I am on my walking around taking
| | 00:03 | pictures and I've got my 24-105, which
is my nice walk-around lens, because it
| | 00:07 | gives me a good focal length range.
| | 00:10 | Note that I have no lens cap on my lens.
| | 00:12 | Now, what I am about say lot of
people aren't going to agree with and your
| | 00:16 | personal choice is just fine.
| | 00:17 | I want to bring up just something for
you to consider, which is, should you keep
| | 00:20 | lens caps on your lenses?
| | 00:22 | I keep lens caps on my lenses when I am
in home and I am storing my lenses, but
| | 00:25 | when I go out to shoot, I take
the lens-cap off and I put it away.
| | 00:28 | Like way away where I am not
ever tempted to put it on the lens.
| | 00:31 | Sometimes in fact I will even leave
them at home. Because if I am out shooting
| | 00:34 | in a street type situation or anytime
where the situation might be changing
| | 00:39 | rapidly and I need to move quickly to
get the shot, I don't want to have to
| | 00:42 | deal with the lens-cap.
| | 00:43 | I have missed shots before because I
pulled my camera out, thought "oh, lens-cap," and
| | 00:46 | taken it off.
| | 00:48 | I know some professional photographers
who actually throw their lens-caps away
| | 00:51 | when they get a new lens.
| | 00:52 | Now, that might seem reckless and dangerous.
| | 00:55 | Bear in mind that I do have a
UV filter on the end of my lens.
| | 00:58 | So, my lens itself is protected.
| | 01:00 | Yes my filter could get scratched and if this
is a $80, $90 filter, that's a little painful.
| | 01:04 | But also remember that tiny
scratches on a filter aren't going to matter.
| | 01:08 | Your camera will focus past them.
| | 01:10 | The important thing is not to preserve a
perfect museum quality specimen of this
| | 01:14 | camera, but to be able to get good shots.
| | 01:16 | And to do that I need to
be able to move quickly.
| | 01:18 | So my personal choice is, is when I am
out, I am a little bit anti-lens cap.
| | 01:22 | I either leave them in the
bag or just leave them at home.
| | 01:25 | Just something to consider.
| | 01:26 | Your own decision is up to you.
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|
|
6. Advanced AutofocusFocus point selection| 00:00 | In this course I've been assuming that
you're already comfortable with basic auto focus,
| | 00:04 | a topic that we covered in
some detail in the Foundations of
| | 00:08 | Photography: Exposure course.
| | 00:09 | So, you should already be habitually
pre-focusing and you should understand
| | 00:13 | what the focus points in
your camera's viewfinder are.
| | 00:16 | You may have already encountered times
when auto focus was difficult or more
| | 00:20 | complicated or just outright
impossible due to weird lighting or complex
| | 00:25 | composition or moving subject matter.
| | 00:27 | Fortunately, your camera probably has
features for dealing with all of these issues.
| | 00:32 | Now, like the Exposure course, we're
keeping this course camera agnostic.
| | 00:35 | I am not going to talk about
specific camera controls or features.
| | 00:39 | But no matter what type of camera or
lens you have, you're going to see features
| | 00:43 | that are very similar to what we're seeing here.
| | 00:45 | So, you'll just need to look those up
in your manual to understand how to work
| | 00:48 | what I'm doing here on your particular camera.
| | 00:51 | Also, here you're seeing something new.
| | 00:52 | You're seeing our mighty smart board,
which is plugged into the output of the camera.
| | 00:57 | So, what you're seeing here is what my
camera would show in its live view display mode.
| | 01:03 | That is what it would show on that
rear LCD screen when I activate live view.
| | 01:06 | It's also a pretty good simulacrum
of what I see when I look through the
| | 01:10 | actual optical viewfinder.
| | 01:11 | So, you're going to be able to
follow along as I do stuff here.
| | 01:14 | Now I have a pretty simple set here.
| | 01:16 | I have three lenses, one
each at a different distance.
| | 01:19 | I want to shoot a shot of this scene
and I want this lens to be in focus.
| | 01:22 | Now I am working with kind of shallow
depth of field here, because I'd like for
| | 01:25 | the rest to fall out of focus.
| | 01:28 | So I am going to half press the Shutter button.
| | 01:32 | As you should already be familiar with,
because this is kind of the default mode
| | 01:35 | on most cameras, it has automatically
chosen a couple of focus points on what it
| | 01:40 | thinks the subject should be.
| | 01:41 | And it's great, because it agrees with me
that the subject should be this lens right here.
| | 01:45 | So it has chosen those two points and
it's focused the lens to this distance.
| | 01:50 | Remember, focus is always about
distance to a particular plane.
| | 01:53 | A certain distance from the lens.
| | 01:56 | But I've changed my mind now.
| | 01:57 | Looking at that picture, I think, "Oh,
| | 01:59 | It would be much better if that
middle lens was in focus." Great!
| | 02:01 | I'll have pressed my shutter button
again to auto focus, and it's no good.
| | 02:05 | It's still deciding that this is the subject.
| | 02:08 | Now, each one of those little boxes is
a potential place that the auto focus
| | 02:12 | system can focus on.
| | 02:13 | Your camera will have maybe a
different number of them and they might be
| | 02:16 | arranged in a different pattern.
| | 02:17 | Fortunately, with most cameras you can
choose the point that you want to focus on.
| | 02:22 | So, what I am going to do here is bring
up a control that allows me to manually
| | 02:26 | select a focus point.
| | 02:28 | Now what you'll see is I can move
around to pick precisely which point I
| | 02:33 | would like to focus on.
| | 02:35 | So, I am going to put this on right
there, on one of the points in the center.
| | 02:40 | I am going to put it down a little bit lower.
| | 02:41 | I'll put it up there.
| | 02:43 | I am looking for a point
that's got some contrast in it.
| | 02:46 | I am going to half press the Shutter
button to focus and sure enough, now my
| | 02:49 | center lens is in focus.
| | 02:51 | This one has fallen out of focus
because of my shallow depth of field and that
| | 02:54 | one back there is still out of focus.
| | 02:56 | So, that's looking pretty good.
| | 02:57 | But yeah, the more I look at it, the
more I think it's that far lens that's the
| | 03:01 | subject of this image.
| | 03:02 | So, I want to focus back there.
| | 03:04 | So, I am going to bring up
again my focus point display.
| | 03:07 | Then I am going to move the little lighted
box over to a point on that lens, and
| | 03:13 | uh-oh, I got a problem here.
| | 03:14 | Because there is no point with this
particular number of focus spots that falls
| | 03:20 | on that thing, which is
what I want to be my subject.
| | 03:23 | However, if I put the spot right there,
it's still choosing a point on the table
| | 03:28 | that's at the same distance as the lens.
| | 03:30 | So, it doesn't matter that is
not actually on that object.
| | 03:33 | It's on a point that's at the
same distance as that object.
| | 03:35 | So, when I half press auto
focus, it's still in focus.
| | 03:39 | So, remember focus is about distance.
| | 03:42 | Now, if it was really low light in here,
my camera might have trouble focusing.
| | 03:46 | A lot of auto focus mechanisms need
contrast in the scene to be able to focus.
| | 03:50 | Others use something called phase detection.
| | 03:52 | Either way, like your eye, they need some
light to be able to see what they're doing.
| | 03:56 | If it was darker in here, when I
half-press the shutter button, this particular
| | 04:00 | camera has something called
an auto focus assist lamp.
| | 04:02 | It's a little light bulb right here
that it can turn on to shine light into the
| | 04:05 | scene to try to create
enough light to focus with.
| | 04:08 | Your camera might have something similar.
| | 04:10 | And if you've ever wondered why
sometimes in low light, it starts shining a
| | 04:14 | light in your subject's eyes or it pops
up the flash and flashes it a bunch of
| | 04:17 | times even though you didn't want flash.
| | 04:19 | That's probably an auto focus assist mechanism.
| | 04:22 | Most cameras that have them
also allow you to turn them off.
| | 04:25 | This can be essential if you're
shooting in a museum, at a wedding, somewhere
| | 04:29 | where it's not appropriate to
have these odd lights shining around.
| | 04:32 | So, you want to turn that off.
| | 04:34 | If you then get back into low light
and a place where it's okay to have that,
| | 04:37 | remember to turn it back on.
| | 04:38 | There is another option that
I can use for focusing here.
| | 04:40 | And that's manual focus.
| | 04:42 | The way we used to do it
before we had auto focus mechanisms.
| | 04:45 | This camera has on it, like most SLRs,
there is a switch that says AF and MF.
| | 04:50 | If I switch it to MF, I can manually focus.
| | 04:53 | And for that, there is
just a ring that I can turn.
| | 04:55 | There is the center lens in focus,
there is the front lens in focus, and there
| | 05:00 | is the rear lens in focus.
| | 05:03 | This is much easier to do when I
am looking through the viewfinder.
| | 05:05 | I've got a more accurate eye on focus.
| | 05:07 | Most live view modes let you zoom in if you
need to, to really double-check your manual focus.
| | 05:11 | Also, fancier lenses have just a manual
focus override built into their auto focus mode.
| | 05:18 | So, I've switched this
camera back to auto focus.
| | 05:21 | So, as you can see, it's still auto focusing.
| | 05:23 | But without having to flip that
switch, I can just grab the manual focus
| | 05:28 | ring and move it over.
| | 05:29 | Don't forget about your manual focus feature.
| | 05:31 | It can be very, very, very handy.
| | 05:33 | Particularly, if you're needing to work quickly.
| | 05:35 | Your auto focus is not getting what you want,
you can just grab that ring and try and focus.
| | 05:39 | A lot of times, manual focus is a
better way to work if you're shooting
| | 05:42 | fast-moving subject matter.
| | 05:43 | You can ride the focus to follow
your subject as it moves around.
| | 05:46 | There're a couple of other solutions
to this particular type of focus and
| | 05:49 | auto focus problem.
| | 05:51 | And we're going to look at
the next one in the next video.
| | Collapse this transcript |
| Center-point auto-focus| 00:00 | Here's what you should
already know about auto focus.
| | 00:02 | When you half-press your shutter
button, your camera focuses in your scene.
| | 00:06 | Where it chooses to focus depends on
what mode you have it in, what focus
| | 00:10 | mode you have it in.
| | 00:11 | By default it's going to be in a mode
where it automatically selects a point to
| | 00:15 | focus from amongst a selection of
focus points, like we're seeing here.
| | 00:18 | This particular camera has this
particular number arranged in this
| | 00:21 | particular pattern.
| | 00:22 | In the last video you saw that you can
manually choose one of these points to be
| | 00:26 | sure that your camera is
focused in the right spot.
| | 00:29 | A lot of photographers, myself included,
take a different approach to auto focus.
| | 00:34 | Rather than going with auto focus point
selection or manually choosing a point,
| | 00:38 | we lock our auto focus point
on the center and here's why.
| | 00:42 | A lot of times if you're trying to work
quickly, you might be shooting and you
| | 00:45 | just don't have time to stop and figure
out which focus point has been selected.
| | 00:50 | As you know, when you half-press the
shutter button it lights up the point that
| | 00:53 | it's chosen, but you've got to
really be in the habit of going "Oh,
| | 00:56 | good, that points on my subject."
| | 00:58 | The problem is if it's not on your
subject, then you have to stop and manually
| | 01:02 | move and select a focus point and
all that stuff we saw in the last movie.
| | 01:05 | Again, if you're trying to work
quickly, it's not entirely practical.
| | 01:08 | Watch what happens if I set my
focus point to just the center point.
| | 01:15 | Now I always know where it's going to focus.
| | 01:17 | I don't have to stop and try and
figure out where it is and override it.
| | 01:21 | I know for sure where it's going to focus,
which is great in a situation like this.
| | 01:24 | I half-press my shutter button and sure
enough it focused right here on this center lens.
| | 01:29 | Wonderful!
| | 01:29 | What if I wanted this lens in focus,
or that lens back there in focus?
| | 01:33 | Well, the good news is I know
where the camera is going to focus.
| | 01:36 | So all I have to do is put
that point on my subject.
| | 01:39 | Now the problem is I've
messed up my composition.
| | 01:42 | But as you probably have already
discovered, if you half-press the shutter
| | 01:47 | button to auto focus, it stays focused
at that point as long as you continue
| | 01:52 | holding the shutter button down halfway.
| | 01:54 | That means as long as I keep holding
the button down I can re-frame my shot
| | 01:58 | back to where I want it, and press the shutter
button the rest of the way to take the picture.
| | 02:02 | I'm not actually taking the picture here
because it messes with our smart board.
| | 02:05 | But the mechanism is put that center
point where I want it, half-press, frame
| | 02:09 | how I like, and focus.
| | 02:11 | That allows you to do things like
we've done here, focusing on something to
| | 02:16 | create a composition that's not
entirely center focused, but it'll also get you
| | 02:20 | around some other problems.
| | 02:21 | Notice that if I put my center focus
point on something that lacks contrast, in
| | 02:26 | this case that white wall, I can press-
and-hold my shutter button down and I
| | 02:31 | never get a confirmation of focus.
| | 02:33 | As we talked about before
auto focus requires contrast.
| | 02:36 | I'm just here holding it.
It's not doing anything.
| | 02:38 | The lens is moving around.
| | 02:39 | I simply cannot focus there
because there's not enough contrast.
| | 02:43 | So there will be times when maybe your
subject lacks contrast, you can't get it
| | 02:48 | to focus, you can put your center point
on something at the same distance that
| | 02:52 | has contrast in it, half press to focus,
re-frame your shot, and shoot that way.
| | 02:58 | One more trick that helps you in a
situation like this or a lot of times in
| | 03:01 | landscape shooting, anytime you're
locked down on a tripod. Let's say that I
| | 03:05 | know this is going to be my subject
and so I've focused my shot and I've
| | 03:09 | reframed and I take the shot, and I look
at it and I go, "Well, the lightings are
| | 03:13 | not quite right," and so I make
some adjustments to lighting. Ugh, great.
| | 03:17 | Now I've got to go back in here and do
this and re-frame my shot and I had it
| | 03:20 | framed just perfectly.
I really don't want to move it around.
| | 03:23 | For times like this where once I set my
focus, I know what I want it to be and
| | 03:26 | I don't want it to change,
| | 03:28 | now that I've got it set, I'm just going
to flip my camera over to manual focus.
| | 03:32 | That locks the focus.
| | 03:33 | The auto focus mechanism is now out of the loop.
| | 03:35 | So now I can just press the button and
take my shot, confident that my camera is
| | 03:39 | focused where it needs to be.
| | 03:40 | I can play with the lights, do other
things, press the button and I'm good.
| | 03:43 | So those are a few focus tips.
| | 03:46 | We're going to look at one more
focus trick in the next movie for
| | 03:48 | shooting moving objects.
| | Collapse this transcript |
| Servo focus| 00:00 | This is the Canon 24-105 EFL.
In addition to its great zoom range of 24-105
| | 00:07 | millimeters, which makes a fantastic
walk-around lens, its four stops of image
| | 00:11 | stabilization, its constant f4
aperture across its zoom range, the low
| | 00:15 | dispersion glass, the red stripe
around the end of the lens, which lets people
| | 00:19 | know that you're a discerning shooter.
| | 00:21 | in addition to all of that,
it makes a great pendulum.
| | 00:25 | Now the problem is if I stick a camera
down there and I want to shoot this lens
| | 00:28 | as it swings back-and-forth, I got
problems, because I'm not going to be able to
| | 00:31 | focus on it very easily. Here's why?
| | 00:34 | Focus of course is a matter of the
distance between the lens and the camera and
| | 00:37 | if I focus right here, it's
immediately swung out of focus, and-- stop that!
| | 00:43 | it's immediately swung out of
focus and my image will be blurry.
| | 00:46 | Now I can try to half press the
shutter button along the way and keep up with it,
| | 00:49 | but it's really difficult to do
when something is moving that quickly.
| | 00:51 | Now, you may think I don't angle my lenses
from the ceiling, so what does it matter?
| | 00:55 | In that case it probably doesn't, but
you probably do maybe take your kids to
| | 00:59 | the park and put them on a
playground swing, shoot your friends surfing,
| | 01:03 | maybe you go on safari and get charged
by a lion and you want to leave some
| | 01:06 | nice pictures behind.
| | 01:07 | Anytime you've got moving subject
matter, you're going to have this issue of
| | 01:11 | trying to keep up with the focusing
process and this is not just about
| | 01:14 | things moving towards you. Even
things just moving across the frame like
| | 01:17 | wildlife or fast-moving sports.
| | 01:19 | Fortunately your camera probably has a
feature called servo focus, sometimes
| | 01:23 | called focus tracking, which can track
the subject in your image as it moves
| | 01:27 | across the frame or forward
and back and keep it in focus.
| | 01:30 | Here's how it works.
| | 01:31 | You put your camera in the servo focus
mode, frame your shot, half press the
| | 01:35 | shutter button, the camera will
automatically identify the moving thing and
| | 01:40 | make constant adjustments to
focus as that thing moves around.
| | 01:43 | To a degree it even works
when you are moving the camera.
| | 01:46 | It can separate
background motion from the subject.
| | 01:49 | So we went to the park and stuffed Jacob
on a swing and I got down on the ground
| | 01:54 | with a wide-angle lens to get a really
dramatic angle and you can see here that
| | 01:57 | I'm just shooting away and I'm not
having to worry about focus at all.
| | 02:01 | Once I'd frame my shot the way that I
wanted, I half pressed the button and I heard
| | 02:05 | the servo focus mechanism startup.
| | 02:07 | You'll hear your lens making lots of little
noises. You'll feel vibration in the lens.
| | 02:10 | I also put my camera into burst mode.
| | 02:12 | In burst mode, as long as I hold the
shutter button down the camera will keep
| | 02:16 | knocking out frames.
| | 02:17 | This particular camera can
do about 5 frames per second.
| | 02:19 | So when it would swing
into frame I'd start bursting.
| | 02:22 | Meanwhile, servo focus is keeping him in focus.
| | 02:26 | Here's what's happening inside the viewfinder.
| | 02:27 | Now this is a simulation that we've
greatly slowed down, but you can see as he moves,
| | 02:33 | he comes to a new point, he
is out of focus, and he sharpens up.
| | 02:36 | It goes to the next frame,
and the camera sharpens up.
| | 02:39 | That's because it's constantly staying in focus.
| | 02:41 | As he comes back in, he
moves in and he sharpens up.
| | 02:43 | This is all happening very, very, very quickly.
| | 02:46 | It's an ideal, very easy way
to shoot moving subject matter.
| | 02:49 | There is a caveat though.
| | 02:51 | You're used to your auto focus
mechanism, when you half press the shutter
| | 02:54 | button, at some point you see a ligh,
light up and you hear that beep that
| | 02:57 | tells you "I've locked focus
and now you can take the picture."
| | 03:00 | And servo focus mode is never
going to lock focus. That's the point.
| | 03:03 | It keeps refocusing all the time.
| | 03:05 | So when you're done with servo focus
mode it's very important that you switch
| | 03:08 | back to your normal focus mode.
| | 03:11 | If you don't, you'll do something that
I've done a lot of times which is I go to
| | 03:14 | shoot something else later and go
well, my auto focus isn't working.
| | 03:17 | Oh, my camera must be in manual focus
mode and I look at the lens and no,
| | 03:20 | it's in auto focus mode and finally, by the
time my subject is left, I remembered, oh,
| | 03:25 | it's in servo focus and I change it back.
| | 03:26 | So just be aware in kind of a
troubleshooting mode that when if your camera is
| | 03:30 | not locking focus, it may have either
been left in servo focus mode or you may
| | 03:34 | have accidentally put it there.
| | 03:36 | So if you regularly shoot moving
subject matter, take a look at your camera's
| | 03:41 | manual to learn about its servo focus mode.
| | 03:42 | How to activate it and any
caveats there maybe about it.
| | Collapse this transcript |
| Focus troubleshooting: What to do when your auto-focus doesn't| 00:01 | So, I found this landscape shot that I like.
| | 00:03 | I've got this big wall of fog
overtaking the small town here.
| | 00:07 | Now, what I like about this
shot is the big wall of fog.
| | 00:10 | The problem is the big wall of
fog doesn't have any contrast in it.
| | 00:13 | And the auto focus system in my
camera needs contrast to detect focus.
| | 00:17 | The idea is where there's more
contrast, there's better focus.
| | 00:21 | This is a type of situation
you're likely to encounter a lot.
| | 00:24 | Maybe it's not a crushing wall of fog, but
it could be anything that lacks contrast.
| | 00:28 | Maybe you're trying to focus on
something that's just a solid color.
| | 00:32 | So, where I am at here is I've chosen
to use only my center point auto focus or
| | 00:38 | the center point of my auto focus.
| | 00:40 | That point is falling in the middle of the fog.
| | 00:43 | So, what I need to do to solve this problem--
| | 00:45 | There are a few different options.
| | 00:46 | I can put the camera back into auto
focus select mode or auto focus point select
| | 00:52 | mode where it will choose
the focus points that it wants.
| | 00:55 | And hopefully, it will
choose one maybe down on the town.
| | 00:58 | If it doesn't, then I can manually
choose an auto focus point that's correct or
| | 01:03 | I can switch to manual focus and
just try to manually focus the lens.
| | 01:07 | Those are all ways of getting
around the problem of initial focus.
| | 01:11 | But because this is a landscape shot,
I am probably going to shoot it several times.
| | 01:14 | I am waiting for the light to get
right, I am waiting for cool fog patterns
| | 01:17 | to come in, whatever.
| | 01:18 | I am going to want to take a few shots of this.
| | 01:20 | So, after I get it focused, I am going
to go around to the auto manual focus
| | 01:25 | switch on the lens, and
switch it over to manual focus.
| | 01:27 | That will lock my focus in.
| | 01:29 | So as long as I don't bump the
manualfocus ring, I'll have good focus.
| | 01:32 | Then I can just stand here, watch the
scene, and knock-off shots as I like them.
| | 01:37 | So anytime you come into a situation
where you would hear that searching thing,
| | 01:41 | you don't hear the auto focus beep,
| | 01:42 | basically, anytime you come into a
situation where your camera is not focusing,
| | 01:46 | those are the ways to work around it.
| | 01:48 | Manually choose a focus point, switch
back to auto focus point selection if you
| | 01:52 | were not on it, manually focus, or use
the tilt and reframe focus technique that
| | 01:56 | we looked at earlier.
| | 01:57 | All of those will get you out of your
low contrast area and hopefully allow
| | 02:01 | your camera to lock focus.
| | Collapse this transcript |
| Filters| 00:00 | One of the kind of annoying things
about digital cameras is that if you come
| | 00:04 | from a film background, especially if
you were shooting with film before there
| | 00:08 | were digital cameras, you regularly
find yourself wanting to say, "You know back
| | 00:12 | in the film days we did it like this."
| | 00:14 | It's really hard to resist.
| | 00:17 | So I'm not even going to try.
| | 00:18 | You know back in the film days we used filters.
| | 00:21 | These days "filter" usually means a small
bit of plug-in code that you run inside
| | 00:25 | of Photoshop or some other image editor,
but filter used to refer exclusively to
| | 00:30 | a piece of glass that you
put in front of your lens.
| | 00:33 | Now it still means that, but these days
you don't typically use filters as much
| | 00:37 | as you used to, because most of what
you use to do with filters can now be done
| | 00:41 | in post-production. But there are still
some filters that are valuable and that
| | 00:44 | can be pretty handy.
| | 00:46 | This is an example of a graduated
filter, you can see that it's darker at the
| | 00:49 | top than at the bottom.
| | 00:51 | We've talked about the limited dynamic
range of your camera compared to your eye,
| | 00:54 | how it's difficult for it to capture
bright sky and dark foregrounds. This is
| | 01:00 | something you could put in front of
your lens and actually dim the sky while
| | 01:03 | preserving the background.
| | 01:05 | This is a big square filter.
| | 01:06 | It's for a particular type of camera.
| | 01:08 | For most of the lenses that you'll put
on your SLR, you'll be just using round
| | 01:12 | filters that screwed onto the end.
| | 01:15 | Your lens should have threads
and the filter just screws in.
| | 01:20 | There are number of different kinds of filters.
| | 01:22 | The one you should be most concerned
about or that you should be most indulgent
| | 01:26 | in is simply a UV filter,
sometimes called a skylight filter.
| | 01:31 | It sits on the end of your lens and it's
there just to protect the end of your lens.
| | 01:36 | It doesn't alter the light at all
and so it's going to help protect the
| | 01:40 | lens from scratches.
| | 01:41 | I have actually dropped lenses
before and they have landed like that.
| | 01:44 | I've dropped my entire camera, it's
landed like that, shattered the filter,
| | 01:48 | the lens has been fine.
| | 01:49 | So it's really, really worth it to
protect your investment and your lenses by
| | 01:54 | investing in some UV or
skylight, sometimes called haze filters.
| | 01:58 | You go out and you spent a $1000 on a
lens, don't buy a cheap filter to put on
| | 02:03 | the front of it because that can
actually degrade the quality. You want to get
| | 02:06 | a filter that is multicoated.
| | 02:08 | That means it's going to have special
chemical coatings that will help reduce
| | 02:11 | flare as light passes through the filter.
| | 02:14 | Another handy type of filter which
happens to be on this camera right here,
| | 02:16 | note we've got two filters. I've got a
UV filter and on top of that I've got a
| | 02:20 | circular polarizer.
| | 02:21 | You can stack filters.
| | 02:23 | And what I've got here is a circular polarizer.
| | 02:25 | It's actually screwed onto the front
of the lens, but I can turn this front
| | 02:30 | element and as I do I can change
the polarization of the light that's
| | 02:33 | entering the camera.
| | 02:34 | There are two things I can
do with the circular polarizer.
| | 02:37 | I can increase contrast,
particularly in skies, clouds especially.
| | 02:42 | I can also use it to eliminate reflections.
| | 02:44 | If I'm shooting even the surface of a
table like this that is very shiny, I can
| | 02:48 | use a polarizer to just
dial that reflection away.
| | 02:51 | I can dial a certain amount
of reflection out of windows.
| | 02:54 | So if you're shooting through glass
a circular polarizer is very handy.
| | 02:57 | Circular polarizer is one of those
filters that you cannot simulate digitally.
| | 03:01 | So it's a good investment.
| | 03:03 | Filters come in different sizes and
the end of your lens will list on it a
| | 03:07 | filter size and I've got that right here.
| | 03:10 | This little symbol, it's a circle with a
vertical slash through it and then it's a 72mm.
| | 03:16 | That's telling me that the filter
size for the end of this lens is 72 mm.
| | 03:20 | So I want to get a lens that is that size.
| | 03:23 | They come in lots of different sizes
and as you would expect, the bigger they are,
| | 03:26 | the more expensive they are.
| | 03:28 | So your fast lenses like this one
0.250, which always have a wide diameter,
| | 03:33 | it's going to cost lot of money
to start putting filters on those.
| | 03:35 | Some other types of filters I have
here and this happens to be a 72mm filter.
| | 03:40 | This is an infrared filter.
| | 03:42 | It filters out all the
light except for infrared.
| | 03:45 | And as you can see it's almost
appears to be completely opaque.
| | 03:48 | Infrared photography is
possible with digital cameras.
| | 03:52 | It's a bigger topic than we want to get
into here, but I screw this onto the end
| | 03:55 | of my lens and then I'm going to be
able to take infrared photos like these.
| | 03:59 | There is a lot of work to get a good
infrared photo, because this filter is
| | 04:03 | blocking out so much light. There are
actual modifications that some people make
| | 04:07 | to their cameras to make them
work better as infrared cameras.
| | 04:11 | Like these images here. Infrared images
have a very distinctive look and it can
| | 04:16 | be worked to get a good infrared
picture with a digital camera, both because of
| | 04:20 | the opaqueness of the infrared filter
and because your camera itself is not
| | 04:24 | really set up for infrared shooting.
| | 04:26 | Some people actually modify digital
cameras specifically for infrared shooting.
| | 04:31 | So you've got the power of your post-
production image editor and you've also got
| | 04:34 | filters that you can put on your
lens to achieve different effects.
| | 04:37 | When you go filter shopping you'll
find filters that can create starburst
| | 04:40 | effects around highlights, that
can change the color of things.
| | 04:43 | That can add diffusion.
| | 04:44 | That can enhance skin tone, on and on and on.
| | 04:48 | When should you use a filter to
get an affect and when should you
| | 04:50 | use post-production?
| | 04:52 | If you are working in an environment
where you need a really quick workflow,
| | 04:56 | maybe you're shooting a wedding or
something and you've got to get home and get
| | 04:59 | those images out to the
client as quickly as possible.
| | 05:01 | If you want the type of affect you
can get from the lens filter that you
| | 05:04 | can also get from an image editor, maybe
it's better at that point to use a lens filter.
| | 05:08 | You won't have to do as much post-processing.
| | 05:10 | Personally, I prefer to shoot my
images as clean as possible, as close to just
| | 05:15 | reality as I can, because then I can
have a lot of different options later.
| | 05:19 | If you've already filtered an image to
say make it more diffuse or to put a
| | 05:24 | starburst pattern on specular
highlights, things like that, I can't take
| | 05:27 | those effects out later.
| | 05:29 | So shooting a more neutral image that I
can filter in post-production gives me
| | 05:32 | more flexibility if I want to repurpose
those images for something else later.
| | 05:37 | Still, filters, especially circular
polarizers, are very valuable effects and
| | 05:42 | absolutely put UV filters on
the end of all of your lenses.
| | Collapse this transcript |
| Auto-focus and live view| 00:03 | One of the things that's really nice
about an SLR is it has a single lens.
| | 00:07 | That's the SL part of SLR.
| | 00:09 | What's nice about a single lens is
it means that my eye, when it looks
| | 00:13 | through the viewfinder, is looking through
the same lens that's exposing the image sensor.
| | 00:17 | The image sensor sits right back
here, directly behind the lens.
| | 00:21 | What's nice about that is it means
that when I am looking through the
| | 00:23 | viewfinder, I am seeing the exact same
composition that the image sensor is seeing.
| | 00:27 | I can also see the effects of
any filters that I put on the lens.
| | 00:31 | In general, it's just a better
arrangement than having one viewfinder for me and
| | 00:35 | another one for the image sensor.
| | 00:37 | Now, for all this to work there have to be
some extra little mechanics inside of your camera.
| | 00:41 | You may know all this already,
but let's take a quick look here.
| | 00:43 | I am going to take the lens off
and what you see here is a mirror.
| | 00:47 | Now, I had said before, the image
sensor sits right back here and that
| | 00:50 | should make sense to you.
| | 00:51 | It needs to be directly behind the lens
so the light gets through to it, and
| | 00:55 | of course there is a shutter in front of the
image sensor, but there is also this mirror.
| | 00:59 | And what the mirror does is it takes
the light that's coming to the lens and it
| | 01:03 | bounces it straight up.
| | 01:04 | It gets up into here, into
something called a pentaprism.
| | 01:07 | In a less expensive camera that would
be a pentamirror, and that light then
| | 01:12 | shoots it straight out back out the viewfinder.
| | 01:14 | Now, the problem is if I open the
shutter to expose the sensor, there is
| | 01:18 | this mirror in the way.
| | 01:20 | Fortunately, the mirror can move.
| | 01:21 | I have got my camera in bulb mode,
which means as long as I hold the shutter
| | 01:24 | button down, the shutter will stay
open and the mirror will do its thing.
| | 01:28 | So you can see here, when I press the
shutter button, the mirror flips up out of the way.
| | 01:32 | You didn't see this
because it happened so quickly.
| | 01:34 | The shutter opened and that's the
image sensor that you are looking at.
| | 01:37 | When I let go of the shutter button, the
shutter closes and the mirror comes back down.
| | 01:42 | That's the reflex or R part of SLR.
| | 01:45 | That mirror moving around thing.
| | 01:47 | So right now I've got light bouncing
off the mirror and coming out here to
| | 01:50 | where my eye can see it, and now I've got light
going all the way through into the image sensor.
| | 01:55 | It's a very clever arrangement, works very well.
| | 01:58 | However, with digital cameras, people expect to
be able to use the LCD screen as a viewfinder.
| | 02:04 | So for that to work we have a problem.
| | 02:07 | And the problem is this: the
autofocus sensors in your camera sit up here.
| | 02:11 | They depend on light being bounced up
into the pentaprism chamber to be able
| | 02:16 | to see and when the mirror comes up, they go
blind because they're not getting any light.
| | 02:20 | So that makes autofocus very difficult
in live view, because in live view the
| | 02:23 | mirror has to stay up all the way.
| | 02:25 | When you put your camera in live view
mode, you probably hear a sound like that.
| | 02:29 | That's the mirror going up and the
shutter opening and those just stay open
| | 02:32 | because the image sensor is there
gathering light and building the 30 frames per
| | 02:36 | second or whatever it needs to build
to put a continuous image back here.
| | 02:41 | Because the mirror is up, the
autofocus sensors are blind, so you cannot
| | 02:45 | autofocus during live view.
| | 02:47 | So the way most cameras get around
this is they have a button so that when
| | 02:53 | you focus or when you press the autofocus
button, the mirror temporarily comes back down.
| | 02:57 | That gets light back to the autofocus sensors.
| | 03:00 | Your camera focuses, then the mirror
automatically goes back up, and now the
| | 03:04 | image sensor can get light, so that
it can start building its live view.
| | 03:07 | This is why in live view mode, when
you hit the focus button, your screen
| | 03:11 | goes blank temporarily.
| | 03:12 | Now, this is a drag if you're trying
to follow motion or track something.
| | 03:15 | If you're really needing to be in the
moment of taking the photograph, you are
| | 03:18 | going to get interrupted
by that focusing process.
| | 03:21 | Because of that some camera vendors
build-in an additional autofocus mode when
| | 03:25 | in live view, and that's a
contrast detecting autofocus mode.
| | 03:28 | And what that means is the mirror
stays up all time so your live view screen
| | 03:32 | stays on all the time.
| | 03:33 | The image that the image sensor is
getting is analyzed for contrast, because
| | 03:37 | where there's more contrast, there's
better focus, and those calculations are
| | 03:40 | used to determine how to focus the lens.
| | 03:43 | The problem with that is it's a
very slow mechanism, because it's very
| | 03:45 | computationally intensive and the
computer in your camera just can't keep up
| | 03:49 | very well with current technology.
| | 03:50 | So that's not the best solution.
| | 03:52 | Another option is you can manually
focus your lens when in live view.
| | 03:57 | What's tricky about that is it's
hard to judge focus on these little LCD
| | 04:01 | screens. Even though this has a big
beautiful LCD screen for telling fine
| | 04:05 | detail, it can still be a little tricky.
| | 04:07 | So these are just all caveats that you
need to be aware of when using live view
| | 04:12 | and trying to autofocus.
| | 04:13 | Now, there are cameras
that get around this problem.
| | 04:15 | Some Sony cameras, some Olympus cameras,
a few others, solve the autofocus and
| | 04:20 | live view problem by putting extra
focus sensors down here or by using a split
| | 04:26 | mirror or a fancy prism or something
like that to get light up here to these
| | 04:31 | autofocus sensors, and then
they can manage their autofocus.
| | 04:34 | Also be aware that when you're
shooting video with your SLR, if it has that
| | 04:37 | capability, the whole autofocus thing is
going to interrupt your video feed and
| | 04:41 | that's no good either.
| | 04:43 | So plainly, this is a complex subject to learn.
| | 04:45 | How it works with your camera, you
need to dig into the live view sections of
| | 04:49 | your camera's manual and learn
exactly what autofocus mechanisms it has,
| | 04:53 | because you're going to want to use
those anytime that you're shooting with
| | 04:56 | your camera in live view mode.
| | Collapse this transcript |
|
|
7. ConclusionMaintenance| 00:01 | Your lens is where your image making
begins, which means it's also where a lot
| | 00:05 | of problems can start.
| | 00:07 | Fortunately, many of these problems can be
prevented with some simple lens maintenance.
| | 00:10 | In general, a lens is a very sturdy
device that can withstand a fair amount
| | 00:14 | reasonable abuse, unless it's an
especially cheap plastic-y model.
| | 00:18 | One way to really reduce the
chances of that kind of abuse is to carry
| | 00:22 | your camera properly.
| | 00:24 | This is particularly true when you're
carrying your camera with a long lens on it.
| | 00:27 | I see this all the time.
| | 00:28 | People walking around with
their lens hanging like this.
| | 00:32 | The problem is, you're
going to bump it into something.
| | 00:35 | It's also not that comfortable, because
with the lens hanging off this way,
| | 00:39 | it's pulling on my shoulder in different ways.
| | 00:41 | It's flopping around more, the
center of gravity is all along.
| | 00:43 | So a very simple fix for this, which is,
take it off of your shoulder, turn it
| | 00:47 | around, and put it back on.
| | 00:49 | Now the lens is not hanging around
out here, and it's much more stable.
| | 00:54 | It's tucked into the small of my back, and
it tends to just stay there as I move around.
| | 00:58 | If I want to hike or climb or
something like that, I can make it even more
| | 01:02 | stable by putting it over my
shoulder and keeping it there.
| | 01:07 | Now I can be pretty mobile this way
and it's not going to move around.
| | 01:11 | So this is particularly true with long
lenses that carrying it this way is going
| | 01:16 | to make the camera much more stable and
greatly reduce your chances of smashing
| | 01:20 | the lens into something.
| | 01:21 | For the most part, your only
maintenance concern with your lens over the long
| | 01:24 | haul is just keeping it clean.
| | 01:27 | Because as we mentioned before, if your
lens gets dirty that can transfer to the
| | 01:31 | image sensor in your camera, and that
can cause real problems with your images.
| | 01:35 | So, keeping your lens clean is pretty easy.
| | 01:38 | First of all, we never ever, ever take
compressed air, a can of compressed air,
| | 01:43 | and use it on our lenses or on our
camera because compressed air has a liquid
| | 01:47 | propellant inside it.
| | 01:48 | If you don't have the can perfectly
leveled, some of that liquid propellant can
| | 01:52 | spray out and it's really sticky.
| | 01:54 | So instead, we use blower brushes for,
or blower bulbs or blower brushes, for
| | 01:58 | cleaning our lenses.
| | 02:00 | So, I can just blow of the front of the lens.
| | 02:02 | Typically, before I go out shooting
with my kit of lenses, if I'm going to go
| | 02:06 | for a while, I take them out
of the bag and I clean them.
| | 02:08 | I'm not so worried about the front of
the lens, because any dust or things on here,
| | 02:12 | the lens is just going to focus past.
| | 02:14 | But if this is dirty and I'm putting it in my
bag, I'm just transferring lens into the bag.
| | 02:19 | It's this end that is the potential
problem area, because this is the end that
| | 02:23 | goes into the camera.
| | 02:24 | If dust gets in here, I'm translating it
or transferring it directly into the
| | 02:28 | camera body where it could get on the lens.
| | 02:30 | So to clean it, again, I go for a blower bulb.
| | 02:32 | You can get these at any photo store.
| | 02:34 | Hold the lens upside down, so that
I've got gravity working on my favorite.
| | 02:37 | I'm just going to blast some air up there,
hoping that I'm dislodging any little
| | 02:43 | particles and things that are in there.
| | 02:45 | Of course, lot of those, you can
actually just see with the naked eye.
| | 02:48 | So if you blow on it a bunch and you
can't get those off, get a blower brush,
| | 02:52 | which again is available at any photo store.
| | 02:54 | This is going to be a something like
this, only smaller, and it's going to have
| | 02:57 | a brush bristles on the end,
and you can actually brush it off.
| | 03:00 | Use a brush designed for cleaning lenses.
| | 03:03 | Don't think that you can get a
paintbrush, or a makeup brush, or something like
| | 03:06 | that, and clean off your lens.
| | 03:08 | No matter how clean that brush may look,
| | 03:10 | what you don't know is how abrasive the
individual bristles and hairs on the brush may be.
| | 03:15 | A brush designed specifically for
cleaning optical equipment is the only thing
| | 03:19 | you want to take near your lens.
| | 03:21 | Now as I mentioned earlier, it is
possible for dust to get inside the sensor
| | 03:26 | chamber of your camera and get on your sensor.
| | 03:29 | You'll know this has happened when
you look at an image and there is a
| | 03:32 | little smudge or a smear.
| | 03:34 | Sometimes they're completely opaque,
sometimes it's just a little shadow that appears.
| | 03:39 | You're usually only going to see it an
area that's kind of flat color like a sky,
| | 03:42 | because another area might be too busy.
| | 03:44 | So if you think you've got sensor dust,
one, the first way to test is look at
| | 03:48 | some other images and see if you
see the same problem in the same area.
| | 03:53 | After that, it's time to get a little
more serious about your dust testing and
| | 03:56 | so you can take some test pictures
to see if you've got a dust problem.
| | 04:01 | Put a kind of not such a telephoto lens,
a more walk-around lens on your camera.
| | 04:06 | Go outside, point it at the sky, switch the
lens to manual focus, and defocus the lens.
| | 04:14 | Go into aperture priority mode and set
to a small aperture and take a picture,
| | 04:18 | because this is going to give you
basically just a blurry shot of bright sky.
| | 04:21 | We want it be an empty sky.
| | 04:23 | If it's the middle of winter where you
are and you can't go outside because it's
| | 04:25 | too cold or the sky is not empty, a
blank wall will do, preferably a white wall.
| | 04:31 | Take a picture, move it into your
computer, see if you can see spots.
| | 04:34 | If you do, then you got a sensor
dust problem and it's time to start
| | 04:37 | thinking about cleaning.
| | 04:39 | There are couples of ways to go for cleaning.
| | 04:40 | First of all, most SLRs these days,
and bear in mind with sensor dust,
| | 04:44 | we don't really worry about that with a
point-and-shoot camera, because you can't
| | 04:46 | take the lenses off.
| | 04:48 | Most SLRs these days have built-in
cleaning mechanisms and you may have seen
| | 04:52 | this when you turn the camera on.
| | 04:54 | When I power it up, it gives me a
message that says Sensor cleaning.
| | 04:59 | What it's actually doing is there is in
front of the sensor a clear glass plate
| | 05:05 | that it shakes and so any dirt on
there gets hopefully shaken off and falls
| | 05:10 | down the bottom of the camera where
there is a little pad of something sticky
| | 05:12 | and it gathers there.
| | 05:14 | You can set your camera to do its
sensor cleaning cycle at power up and power
| | 05:19 | down, either or, or
you can set it to do both.
| | 05:24 | If you are the type of person who
walks around with your camera off and you
| | 05:27 | like to be able to just switch it on,
have it boot up really quickly so you can
| | 05:30 | start shooting, you might want to set it so
that it doesn't clean the sensor at power up.
| | 05:35 | That will make it come up
to speed a little bit faster.
| | 05:38 | The same menu where you choose those options,
there is probably an option to clean now.
| | 05:42 | You pick that, and it'll shake its little
glass plate, and try and dust off the sensor dust.
| | 05:47 | So if you see that you have a dust
problem, first thing to do is if your camera
| | 05:50 | has a cleaning mode go in and activate it.
| | 05:52 | That'll shake the thing around.
| | 05:53 | You can then go do another test picture
and see if you still have a dust problem.
| | 05:57 | If that doesn't work, you have a couple options.
| | 06:00 | You can send the camera into the
manufacturer and have it cleaned.
| | 06:04 | Most SLR makers have a page on their
website you can go to and they give you
| | 06:08 | very easy explicit directions for
sensor cleaning, how to send it in, and
| | 06:12 | they're usually very speedy about that.
| | 06:14 | It kind of depends on where you are,
how far the camera has to go to a
| | 06:17 | service center that can clean it.
| | 06:19 | That is the safest, most thorough way
to get your sensor cleaned and very
| | 06:22 | often not only will they clean the sensor, but
clean up some of the other bits of your camera.
| | 06:26 | So if you got dust in the viewfinder, or
sometimes even dirt in the LCD up here,
| | 06:30 | they can clean that stuff off.
| | 06:32 | If you're in hurry, if you need the
sensor clean now because you've got a shoot
| | 06:36 | or you just don't want
to be without your camera,
| | 06:38 | you can try to clean the sensor yourself.
| | 06:40 | Now I do this a lot.
| | 06:41 | I clean my own sensor.
| | 06:42 | I've never had any problems. Either
I've just been lucky, or I don't know.
| | 06:48 | But you can damage the
sensor when you're cleaning it.
| | 06:51 | So the first thing is if you are not
real comfortable with hand-eye coordination
| | 06:55 | and using tools, don't do it yourself.
| | 06:58 | Second thing is get the right
supplies for cleaning your sensor.
| | 07:01 | You do not want to use anything other
than gear designed for sensor cleaning
| | 07:06 | when you're working on inside of your camera.
| | 07:07 | Now here is how it works when it
comes time to clean your sensor.
| | 07:10 | The first thing is you take the lens off,
because you got to get to the sensor.
| | 07:13 | If we look in here, we can
see this is the mirror chamber.
| | 07:18 | Here is the mirror.
| | 07:19 | This is what bounces light up into the
pentaprism that goes out to the viewfinder.
| | 07:25 | I can tell the camera to flip that up, that
mirror up, so that I can clean the sensor.
| | 07:30 | I do that in the same menu where I
pull up the sensor cleaning mechanism.
| | 07:35 | If your camera doesn't have a control
to do this, but it has a mirror lockup
| | 07:39 | feature, which a lot of cameras have
because that allows you to lock the mirror
| | 07:42 | up to reduce vibration during long exposures,
| | 07:44 | that will work just as well.
| | 07:46 | You want to be sure your battery is
charged or the camera is running off of the
| | 07:49 | wall power, because we're
going to be working inside here.
| | 07:53 | We're going to have tools in there.
| | 07:54 | We don't want the power to die and
the mirror to come down in the middle of
| | 07:57 | that because it could damage the mirror.
| | 07:59 | So I'm going to tell it to flip the
mirror up now, and it's asking me if I'm
| | 08:03 | really sure that I want to
do this and I am really sure.
| | 08:07 | So there it goes and now we're
actually looking at the sensor.
| | 08:09 | That's where all the magic happens
inside the camera. It's right there.
| | 08:12 | Now the good news is, as I said before,
there is a clear glass plate in front of it.
| | 08:16 | I am never actually
going to be touching the sensor.
| | 08:19 | So my next step is to
figure out where the dust is.
| | 08:23 | Now if I had done a shot before
like I said of the sky or a wall,
| | 08:28 | I could look at that and try and zero
in where it might be. Remember that it is
| | 08:31 | going to be the mirror image.
Or I can use a special tool.
| | 08:34 | I have here a sensor loop.
| | 08:36 | This is made by a company called VisibleDust.
| | 08:38 | Visibledust.com is where their stuff is located.
| | 08:41 | They are a company that has been
around for years, designing material
| | 08:45 | specifically for
cleaning fine optical equipment.
| | 08:47 | Microscopes, telescopes, all that kind of stuff.
| | 08:49 | They really know their stuff.
| | 08:51 | They know how to build tools that
are not going to damage your camera.
| | 08:54 | I really recommend VisibleDust.
| | 08:56 | So they make this sensor
loop tool thing, which is cool.
| | 08:59 | I can put it on here,
and it's lit on the inside.
| | 09:01 | There are little light bulbs inside.
| | 09:03 | So I can put it here.
| | 09:04 | Now when I put my face over to look at
my sensor, because there are those lights
| | 09:08 | in there, I can still see.
| | 09:10 | One thing that's tricky is
when you look at the sensors,
| | 09:13 | you can see here it's got this weird
moire holographic quality to it.
| | 09:18 | Your eye is going to look deep into that.
| | 09:20 | It's going to focus past the surface
of the sensor, because of that kind of
| | 09:23 | optical illusion thing that is going on there.
| | 09:25 | So it can take a while to learn to focus
your eye on the surface where the dust is.
| | 09:28 | This particular sensor is actually clean.
| | 09:30 | It doesn't have any dust in it, but I'm
going to step through the cleaning stuff
| | 09:34 | anyway, but what you're
seeing here is a very clean sensor.
| | 09:37 | We'll see if it stays that way,
because then I'm just sitting here with the
| | 09:40 | camera open like this.
| | 09:41 | So, there are three types of dust.
| | 09:43 | There are simple particles that
sit on the surface of the sensor.
| | 09:47 | There are bits of moisture
that can get on the sensor.
| | 09:50 | Those kind of leave stains. Or you can
get a bit of moisture that then attracts
| | 09:54 | a particle, and that's just really bad news.
| | 09:56 | So we've got multiple ways, kind
of stages we go through for cleaning.
| | 09:59 | The first thing is we go
back to our blower brush.
| | 10:02 | So again, I'm going to turn the camera
upside down to get gravity working with me.
| | 10:05 | I am taking this and I'm
actually going inside the sensor chamber.
| | 10:09 | Here I'm being very careful not to
touch the sensor or the mirror, which is now
| | 10:13 | up above, and I'm just blasting away.
| | 10:16 | If I had seen a bit of dust in there,
I would be trying to aim specifically at
| | 10:21 | that dust, hoping to dislodge it.
| | 10:23 | So I do that and now I would do another test.
| | 10:27 | I would either take the sensor loop and
look at it again or I would go outside
| | 10:30 | and shoot another picture.
| | 10:32 | Come back in. If the dust is still
there, I might try blowing it again.
| | 10:35 | I might try zeroing in on the bad spot again.
| | 10:37 | Do another test, come back in.
| | 10:39 | If it's still there, it's time to go
to the next tool and the kind of next
| | 10:44 | more invasive step, which is a brush.
| | 10:48 | Again, just as with cleaning your lenses,
you don't want to use just any brush.
| | 10:51 | You want to use a brush designed
specifically for sensor cleaning.
| | 10:55 | Think about how small this sensor
is right there. You can see it.
| | 10:59 | It's a very small rectangle.
| | 11:00 | In this case, it's got millions of
pixels on it, which means an individual pixel
| | 11:06 | is much smaller than the
diameter of a single brush bristle.
| | 11:10 | So, one tiny little brush size scratch in
front of the sensor could really mess things up.
| | 11:15 | So I want to be sure that I'm using a
brush that's designed for sensor cleaning.
| | 11:19 | This brush is, and it's very cool,
the bristles I know are safe to be rubbing
| | 11:22 | on that glass plate in front of my
sensor and it's got batteries in it and a
| | 11:26 | button on the side.
| | 11:27 | When I push the button, it does this.
| | 11:30 | So the idea here is not that I put
it on the sensor and spin it around.
| | 11:33 | What's going on here with the
spinning is one, I'm hopefully through
| | 11:38 | centrifugal force flinging any dust
that was there before off of the brush.
| | 11:42 | But also I'm charging the
brush with a static charge.
| | 11:45 | So now when I go in and start brushing
it on my sensor, in addition to the brush
| | 11:50 | dislodging dust, hopefully the
static charge is kind of sucking it up.
| | 11:54 | I bring it out here.
| | 11:56 | I clean off the dust.
| | 11:57 | Maybe I do that a couple of more times.
| | 11:58 | Then I do another test. Again,
either with my loop or by going outside and
| | 12:02 | taking a test picture.
| | 12:03 | If that still doesn't work,
then I might kind of at Defcon 5.
| | 12:08 | I'm not panicking yet,
| | 12:10 | but I'm going to the really
kind of distasteful next stage.
| | 12:14 | This is a swab designed
specifically for cleaning a sensor.
| | 12:17 | It's kind of like a big
Q-tip, but not abrasive at all.
| | 12:21 | There is a special
cleaning fluid I can put on here.
| | 12:23 | I do that and then I rub it on the
sensor and it just-- you are thinking this
| | 12:28 | is my $1500 SLR, and I am smearing a liquid
on the image sensors, is it really a good idea?
| | 12:34 | Anyway, then you turn it over and you
dry it off and you go to check again.
| | 12:37 | This is the part that's really
distasteful that you hope that you don't have to do.
| | 12:41 | Again, after each time I would take my
loop or go to a test shot and make sure
| | 12:45 | that I had actually tackled the dust problem.
| | 12:47 | When I am all done cleaning, I turn
the power on the camera off and the
| | 12:53 | mirror comes back down.
| | 12:55 | So now I want to get lens on as quickly
as possible, because having just gotten
| | 12:58 | rid of the dust, I don't want it coming back.
| | 13:00 | Before I do that though, I might want to
take a look at these, the contacts on my lens.
| | 13:06 | There are these little contacts here
and they match up with these contacts
| | 13:09 | inside the camera body.
| | 13:11 | This is how the lens communicates with the
camera, all the automatic features on the lens.
| | 13:15 | Autofocus, image stabilization, the
control of the aperture, that information is
| | 13:20 | all send through these
from the camera into the lens.
| | 13:22 | If these get dirty, I might find my
lens behaving a little bit strangely.
| | 13:27 | It might be that autofocus doesn't work
every time I try, or image stabilization
| | 13:30 | doesn't turn on, or just in
general the lens acts a little flaky.
| | 13:33 | If you're having some lens problems,
first thing to do is take the lens off,
| | 13:36 | clean the contacts. That can just be a
Q-Tip or even the end of your shirt
| | 13:40 | and just wipe it off.
| | 13:41 | We don't use the end of our shirt of
course for cleaning the lens. Wipe that off.
| | 13:46 | Put it back on.
See if it fixes it.
| | 13:47 | If it doesn't, then your lens is
probably broken, and it's time for it to
| | 13:51 | go into the factory.
| | 13:52 | Now these are sturdy machines.
| | 13:55 | They can go through a lot and
withstand a lot of wear and tear and a lot of
| | 13:59 | foul weather and a lot of the
abuse, and still take great images.
| | 14:03 | But even just a little bit of
dust can get in there and though it won't
| | 14:06 | necessarily ruin an image,
| | 14:08 | it will certainty make you have
a lot more image editing to do.
| | 14:11 | With just a little bit prevention,
making sure that the camera end of your lenses
| | 14:14 | stays clean, making sure that you're
careful when you change lenses, you can
| | 14:19 | keep that from happening.
| | 14:20 | So, basic maintenance is very simple.
| | 14:22 | For more advanced maintenance, check
the web site of your camera vendor. They'll
| | 14:26 | have places where you can go, web site
pages you can go to, to easily figure out
| | 14:30 | how to send your camera.
| | 14:31 | If you do decide to take sensor
cleaning into your own hands, VisibleDust.com
| | 14:37 | sells everything that you need.
| | Collapse this transcript |
| Micro-focus adjustments| 00:01 | Some SLRs have an option for
something called Micro Focus Adjustment.
| | 00:05 | This allows you to tell the camera
that when it's using a specific lens,
| | 00:09 | it should alter its autofocus
mechanism to compensate for the focused
| | 00:12 | peculiarities of that particular lens.
| | 00:15 | Micro focus adjustment is only
significant if you're talking about shooting with
| | 00:18 | the aperture full open on a very fast lens.
| | 00:21 | When shooting with this lens at full wide,
you might find that focus is a little off.
| | 00:26 | Now, sometimes this is because some
of the internal lens elements are out
| | 00:29 | of alignment and the micro focus
adjustment feature will let you compensate for that.
| | 00:34 | The camera will remember the
adjustment settings for that particular lens.
| | 00:37 | So that next time you use it,
your camera will know to compensate when focusing.
| | 00:41 | Now, the thing is when you're
shooting really wide, your depth of field is
| | 00:45 | so shallow that just a slight movement
in and out with your camera can throw
| | 00:49 | your image out of focus.
| | 00:50 | So, before you go worrying about
whether your autofocus is working with a
| | 00:54 | particular lens, you want to be sure
that your focus problems aren't simply
| | 00:57 | because of depth of field.
| | 00:59 | However, if you're a studio shooter or
if your lens is just plainly out of focus
| | 01:03 | and you can't get it working, then
it's well worth considering tweaking the
| | 01:06 | micro focus adjustment settings.
| | 01:08 | If you find that you want to perform
this type of adjustment, then you should
| | 01:11 | look into the Lens Align from rawworkflow.com.
| | 01:15 | It makes performing micro
focus adjustment very simple.
| | 01:18 | We're not going to go into the
specifics of micro focus adjustment features
| | 01:21 | here, because they vary from camera to camera.
| | 01:23 | And right now they're mostly only
available on higher-end cameras.
| | 01:27 | So, if you are interested in this,
check your manual for details.
| | Collapse this transcript |
| Goodbye| 00:01 | That's it. I don't have anything else to say about lenses.
| | 00:03 | You've heard it all.
| | 00:05 | And I know there was a lot of stuff to
hear between what we've covered here and
| | 00:08 | what you have to know about
exposure to get a good shot.
| | 00:11 | There is a lot of stuff to remember when
you're out taking a picture. Don't worry.
| | 00:14 | It gets easier with practice.
| | 00:16 | And as you shoot more, you'll
understand that some things that you got to
| | 00:20 | remember are relevant to one situation and
others are to another and you won't have to
| | 00:23 | sit and parse through this huge
mess of the information and knowledge.
| | 00:27 | I hope what you've come away with
is a fundamental foundation level of
| | 00:31 | lens understanding.
| | 00:32 | Not recipes for particular situations,
but a deeper understanding of focal
| | 00:37 | length and how it impacts your image,
lens speed, and aperture, and all of
| | 00:41 | the other things we've discussed.
| | 00:43 | With that level of understanding, you'll
be able to solve your own problems when
| | 00:46 | you get out in the field, rather than
getting hung up on thinking that it's only
| | 00:49 | one simple set of solutions
that applies to any problem.
| | 00:52 | So, stick the lens on your
camera, get out, and go shooting.
| | 00:55 | Because it's practice that's going
to make you a better photographer.
| | Collapse this transcript |
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