Join Ben Long for an in-depth discussion in this video Understanding the internal light meter, part of Introduction to Photography.
- Before you take a picture your camera needs to be told what shutter speed to use, what aperture setting to use and what ISO setting to use. Now depending on how you have your camera set up you might have to specify all those parameters or you might only have to specify one or two. Or you might not have to specify any at all if the camera is in full auto mode. However, whether it's you or the camera making these choices there's still the question of what the parameters should be set to. Answering that question is what a light meter is for.
A light meter is a sensor that lives inside your camera. It can look at the light that's coming through the lens, measure it and then calculate shutter speed, aperture and ISO settings that will give you a good overall exposure. You know people often refer to sliced bread as being the measure for the greatest thing and I think they only say that because they never tried to calculate exposure settings without a light meter. Doing that is much harder than slicing bread. So I would say that the light meter is the greatest thing since the light meter actually.
Modern meters are incredible pieces of technology that can handle incredibly complex lighting situations. Most of the time your camera's light meter will choose good settings. But there are times when the meter can get confused. But as you get more experience it will become easier to know when you might need to override the meters ideas. After you've framed your shot you activate the light meter by half-pressing the shutter button. So about halfway down you're gonna feel the button give a little bit. That's the point at which the camera activates the meter.
It does some other things at this point as well. It focuses, calculates some color settings. We'll talk about all that later. When you have half-press the meter measures the light in the scene, it analyzes it and then it sets the shutter speed and aperture on the camera. It might also set ISO depending on whether your camera is set to Auto ISO. It then beeps at you to let you know that it's done its calculations. It might also flash a little light in the viewfinder. And then it tells you what settings its chosen. In your viewfinder or underneath the viewfinder some numbers are gonna appear.
So what you're seeing here on the monitor is what my camera is seeing right now. We're looking at this nice little still life of these old cameras and you can see some status indicators down here. This is showing me my battery life, this is showing me how many pictures remain on the card, how much space I have on the card. if I half-press the shutter button a bunch of new stuff appears. Now you didn't hear it beep and that's because when we're taking the video out of the camera to show on this monitor it kills the beep. Normally I would have heard it beep right about then but I'm seeing some other things here.
I'm seeing 50, 5.6 and ISO 400. These are the exposure settings that the light meter has chosen. 5.6 is my aperture setting. That's a measure of the size of the opening of the aperture in the lens. 50 is my shutter speed. This is a fraction. It's the denominator of a fraction. So what this means is 1/50 of a second. Your camera might show things in a different order. in different places in the viewfinder. It might actually write out an entire fraction.
It might say 1/50. But this for right now is the only number that I want you to worry about. This shutter speed number right now. We'll talk more about it later. So now that it's beeped I look at those numbers, i see what they are. If I'm okay with them I can then press the shutter button the rest of the way and the camera takes a picture using those settings. Half-pressing the shutter button like that is a critical habit that you need to develop right away.
If you've ever missed the moment you were trying to photograph because there was a lag between the time that you pressed the button and the time when the camera actually took the picture that's probably because you mashed the button all the way down like that. it takes time for the camera to meter the scene, to focus, to do its other calculations that it has to do. And if you don't give it that time by half-pressing the button and waiting for it to tell you that it's ready then you're gonna miss the shot. So how do you know if the settings that you've chosen are good? That's a huge question that depends on what details you want to capture, what type of image you visualize.
What you might want to do is post-production. In this course we're only going to concern ourselves with one level of exposure analysis. Like I said, that's shutter speed and we're gonna look at that because of the effect that it has on the sharpness of an image.
Then it's time to take to the field and examine the rest of the factors that influence the quality of your photographs, including light metering, focus, composition, and flash. Ben also introduces techniques for shooting portraits and shows what you can do with an image editor in post. Last but not least, he'll provide a roadmap for learning more with the lynda.com extensive library of photography training. The path to becoming a better photographer begins with the first step. Start here!
- Exploring cameras and lenses
- Understanding media
- Controlling exposure
- Composing with autofocus
- Shooting portraits
- Understanding form and geometry
- Exporting and editing digital images