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This weekly course covers the most common questions videographers encounter when shooting and editing with DSLR cameras, from choosing a frame size and frame rate to understanding moiré. Authors Rich Harrington and Robbie Carman will also help you understand the impacts of compression and the difference between cropped (or micro 4/3rds) and full-sized sensors in cameras, and much more. This continual FAQ guide is a handy way to find the answers to the questions that plague you the most.
Male 1: Okay, so Rob, we've got a whole collection of gear here. Let's start. Male 2: We usually do. Male 1: Yes. Male 2: Male 1: Yes. Let's start with that prime ingredient for getting shallow depth of field, the Bokeh, the Bokeh, whatever you want to call it. And that is actually a prime lens makes this a lot easier, right? Male 2: Well, right. I mean you, we talked about when we, you know, did our overview of the subject was that, you know, the one of the distinguishing things about a rack focus is changing the viewers attention, right. And one of the most distinguishing factors of prime lenses is that they have very wider, keep, possibly very wide fixed aperture.
And what that allows you to do is create the very nice sort of soft background border that you talked about Rich. And when you combine that with moving the focus plane, you can quickly focus the viewers attention, creating nice smooth and subtle rack focus techniques. Male 1: Yeah, and what we have here is a collection of prime lenses. And I just want to sort of give you an overview of what you're looking for. You know, for example here, I have a modern prime lens. Male 2: Mm-hm. Male 1: This one is from a company called Sigma. Male 2: Yep. Male 1: And it's a 1.4, which is a very wide open aperture.
This is an 85 millimeter prime. Very common type of lens for shooting portraits or perhaps interviews. Although it does get a bit expensive. One of the cheapest prime lenses you're going to be able to pick up is, for a modern lens, is going to be either a 35 or a 50 millimeter prime. Male 2: Sure. Male 1: And that's great, except those may or may not even have a focus ring on them as you're working. Male 2: That's true and, you know, the thing about, you know, to recognize again we've talked about this in previous episodes. Is that the faster aperture, that lower number, 1.4 versus 1.8 and so on, is going to give you that nice, sort of soft kind of background blur.
The thing about those really fast apertures though Rich, when you're trying to pull focus, and doing a rack focus, is that at a low aperture number, you know, say 1.2, 1.4. Male 1: Yeah. Male 2: It can be very difficult to find the individual point that's truly supposed to be in focus. Male 1: Oh yeah. If you're shooting in a low light situation, that could be a very, very small number. Now, what I've got here is an older style lens. This is a 2.8 lens. Male 2: Mm-hm. Male 1: But it has a very wide aperture. It's letting in a lot of light there.
And I'm able to rack focus here between elements. Now I'm just going to tilt up here. We're actually looking out into the studio. And you see that the studio itself, very soft focus. There's some of our crew on set. Yep. I've got my monitor in focus here. And behind them is the crew. Well if I animate that, notice now that the monitor in the foreground could go soft. And the crew behind it is in focus. Now as we pan across the studio here, you know, the camera in the background, out of focus.
While we rack from that, to the foreground camera, to find focus. And that's really quite simple. All that's happening there, is I'm turning the dial. Male 2: Mm-hm. Male 1: And one of the things I like about these older prime lenses, is that you have such a huge range. Male 2: Sure. Male 1: And that's actually what you've got here. Male 2: Yep. Male 1: Now, older prime lenses have really two benefits. One, they don't have any auto focus capabilities most of the time and you're like, but I love auto focus, well that's not why you have a prime. Male 2: Right. Male 1: And a prime lens you want that great fine control.
And so if I'm looking at this modern prime here, and I turn that. Male 2: Doesn't have much play. Male 1: Yeah. You know, you see that that's probably Male 2: Half a turn, maybe? Male 1: Not even. Like, you know, my finger's here. I hit the other end. That's like a fourth of the lens, if that. Maybe even a fifth. This older style one, as I turn between, and you see the different dials there. Male 2: Mm-huh. Male 1: I've got tremendous amount and I even have the physical distance marked out for the different feet and meters. Male 2: Yep. And you had that in a little window on the other one too but, I, I see your point.
Now, again, I, I get back to this thing about the faster lenses and, you know, we're talking about pulling focus and sort of creating this rack focus effect. Male 1: Yeah. Male 2: The thing that I find sort of challenging, though, is a lot of people tend, because it just creates that nice soft background blur, to shoot with very fast lenses of 1.2, 1.4. And then they attempt to pull focus. My point that I've made a few times. Male 1: You'll never find focus. Male 2: You'll never find focus. And this is my, my thing. And made this this point a few times over various episodes. Is that when it comes to focusing, you need to be precise.
And you also need to practice that pull and that, and that, you know, that rack. Because especially at very wide open apertures. It's going to be, more difficult to find repeatable places when you're pulling focus and rack focusing the camera. Male 1: Well in this case here, like, I'm at 2.8. Male 2: Mm-hm. Male 1: And I would practice that. I can go here and rack between. Male 2: Yep. Male 1: But one of the things I can do is sort of memorize my body position. So as I'm getting that down. Male 2: Yep. Male 1: I can look at the position of my arm.
And kind of get some muscle memory, that's one way. As you see here, we have a view finder attach, putting a loop on that and really seeing it in a large image. Male 2: Makes sense, sure. Male 1: You know, looking at the back of your thing, oh, I think I'm in focus. It all looks in focus until you put it on a bigger screen, but if I change that F-stop, I'm just going to go up a little bit here, obviously. Male 2: Making it darker. Male 1: I can change the ISO. Male 2: Right, yeah. Male 1: Check out our exposure triangle episode if you missed that. So I bumped that back up a bit, and those F stop readings are saying zero because I'm on a non CPU data lens.
This is an old style lens. Male 2: Right. Male 1: But look at how the whole front of the camera and back of the camera is essentially in focus there. And, as I'm rack-focusing, it's not making as much of a difference. So you have to split the difference with that F stop. Male 2: Yeah, and that's a great point, too, Rich, is that, you know, if you do want to shoot at, you know, stop down, so a higher F stop number, that difference in, you know, the perceivable difference in your rack, is less. Male 1:Yeah. Male 2: So, it's kind of a catch 22 either way, and I think you're right about finding that sweet spot. Because if you shoot wide open, you can find it difficult to even find focus in the first place, and then find repeatable focus as you're racking.
And then the opposite side of the spectrum is if you're in you know, if you step down and you're shooting a larger number say F 5.6, F 8, something like that. The rack is actually going to be more hard to detect, right? Male 1: Yeah. Male 2: Because, you know, everything is kind of already in focus, and so it's just minute movements. Male 1: Now I would recommend, as you're balancing this out, you nail the point. Practice, practice, practice. Male 2: Yep. Male 1: One last thing to point out here. I have this 2.8 lens on a crop sensor. Male 2: Uh-huh. Male 1: A crop sensor is not going to be as prone to showing that soft bokeh.
Male 2: Sure. Male 1: You know a larger frame sensor, more sensitivity. You're going to get that so you know, the difference here between a crop sensor and a full size sensor will affect it. If I'm using a cropped sensor camera body, it's going to be really important to be getting those higher quality prime lenses that are getting you know, below 2.8. I can still pull it off just fine. But that's where the tripod comes in handy. That's where you want to get the right balance. Male 2: Of course. Male 1: Notice as I go through, it's all about practice and you could find that as we rack between the different positions.
Male 2: Absolutely. Now I want to make one last sort of aesthetic comment. Male 1: Yeah. Male 2: And that is, in my opinion, as we mentioned when we first started talking. That you know, rack focusing is one of those things that can be used to sort of enhance viewers' attention. Male 1: Yeah. Male 2: Help tell the story and that kind of stuff. One of the things I find a lot of shooters doing is not paying attention to what they're actually shooting. Male 1: Right. Male 2: Right? In other words, you know, one, some of the best rack focus that you've seen is motivated by perhaps, the dialogue. Male 1: Right. Male 2: Right? So, you know, somebody start saying something, and it's a quick focus.
It's a quick rack in between there, right? Male 1: Right. Male 2: Too quick, too quick, it can seem a little jarring, right, so. Male 1: Right, we're going from the person saying the line to the person that they were talking to, rack focusing between the two actors. Male 2: Right. Male 1: Absolutely takes practice. That's a whole separate thing. Male 2: Yeah. Male 1: You can kind of do that in post a little bit. Male 2: A little bit, a little bit. But my point is, you know, as you're, as you're practising rack focuses. Try to get to know your content well and kind of have it be more motivated than simply just moving your hand on the lens. Male 1: Right, yeah I see that happen all the time, like, why do you rack focus in the middle of his sound byte, I needed that.
Male 2: Right, exactly. Male 1: I didn't need it in the middle. Male 2: Cool. Male 1: Now alright, when we come back we're going to switch from prime lenses to zoom lenses. And talk about a couple of dangers, what you really have to look out for, if you're going to be shooting on a zoom lens and you want a rack focus. Male 2: Yeah. Male 1: There are a couple things that can get in the way. Male 2: Absolutely. Male 1: We'll be right back.
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