Choosing Your Frame Rate And The Exposure Triangle
Frame rate. This will often depend upon the project you're working on. If we're working for a client, that's one of the first things I ask is what frame rate do you want us to shoot at? A lot of times people say 24 frames per second has that kind of filmic look, 30 tends to be standard, I think more for broadcast. Then we'll sometimes choose 60p or 60 frames or 120 frames if we want to then slow the footage down, do some slo mo stuff. I think the surf stuff, actually, when we do the edit, we'll slow that down because I shot that all in 60. That will also determine your resolution, or maybe the vice versa. The resolution will sometimes determine your frame rate because if you decide I want to shoot at 4K, like in the case of the Phantom 4, you shoot 4K, it doesn't have the horsepower to do 4K plus 120 frames a second, as much as I'd love that. That would be amazing. So, depending upon what I'm after. Usually, I'm outputting, these days we're still outputting to 1080, a lot of us. So you...
say, well, I'm going to output to 1080, no big deal, I want to get that slo mo shot. Let's shoot at 120 frames per second at 120, and we're good to go. So, frame rate and resolution. Now, exposure triangle. Anybody familiar with the exposure triangle? Yeah, okay, so we got, yeah, yeah, so we got half of us that kind of have camera backgrounds. This is just a simple concept. It's not even really a triangle, it's just three things. We call it the exposure triangle because it's a thing. Aperture, ISO, and shutter speed. ISO is your film speed. It's how sensitive or how gained up your camera is. With some systems, you're really not dealing too much with aperture. Like, for example, the Phantom has a fixed 2.8 aperture. What is the exposure triangle? It's basically the three items that affect your exposure. The exposure being how your the light value from the darks to lights of your image. In the case of the Phantom, we don't have to worry so much with aperture because that's fixed at 2.8, but we do have a shutter speed choice to make and we do have an ISO or a film speed choice to make. If we're at 2.8, we're outside on a super bright, sunny day and we decide to shoot at 24 frames a second, typically the role that we follow as cinematographers for natural motion blur is we double our shutter speed. So if we're shooting at 24 frames per second, we want to shoot at 1/48 of a second for our shutter speed. There's usually not that option, so we go to the nearest, which is usually 1/50 of a second. The reason why we do that is because we want natural motion blur. When we're shooting video, if you shoot too high of a shutter speed, then things start looking real staccato. Like, if you were just to do like this in front of your face here with your hand, you'll see motion blur. That's what we're used to. That's a natural look. By doubling our shutter speed, or making sure that our shutter speed is twice as fast as our frame rate, that is just our go-to. It gives a nice-looking, natural natural motion blur. The problem comes when we are out there, we've got an aperture of 2.8, which is pretty wide open, and then we have our shutter speed at 1/50, which is pretty slow. And then our ISO, it's super bright, so we have our ISO all the way down to 100. What most of you, if you've got this experience, trying to film at those settings on a bright, sunny day, it's way blown out. It's too bright. Right? Before I move on to the next section, anybody have questions about the exposure triangle? Yeah. It's just your three basic things. No matter what camera you pick up, these are the three items that you need to adjust to get your proper shutter speed. Of course, as we know, when you adjust your aperture, we do this with a changing impact on depth of field. The smaller our aperture, the longer the depth of field, the more everything's in focus. Whereas the larger the aperture, it's a narrow depth of field. That's why everybody loves those large, full-frame sensors with that shallow depth of field. Real artsy kind of look. Shutter speed, of course, as we change it, it affects our motion blur and ISO. When we go up with ISO, we usually get what?
Noise, yeah. In these little, these little sensors in these cameras, I don't like to push the real small sets of cameras past ISO 400. You really start to see the noise crop up. It's usually not an issue when you're outdoors. It's bright. On the Micro Four Thirds sensor that's in the Inspire, I don't like to push it above 800. Not only do you get noise, but the colors kind of just seem less true. I find that the image, while you can push it, you start having to do more noise reduction in post and stuff like that.