Now as we've been going through these different exposure modes, I haven't really got too specific about numbers, the exact values. So let's go through a couple of different scenarios, exposure values, to figure out, well, how do I figure out the specific shutter speed and aperture for some different situations. Let's start with freezing motion. So, we have something that moves very quickly. Bald eagle coming into a river to pull a fish out of it. Okay, we want to have this nice, and sharp, and clear, we want to see the eyes, and the beak, and the talons, and so forth, so we're gonna need a fast shutter speed, but we need to get everything else set up on the camera properly. So let's take a look at all of the different options that we have and this is kind of a bit of a game where you can start to decide what needs to go where. Now, the first thing is, I'm a positive, I have hope for the future and so my hope is to be able to shoot this picture at ISO 100, which is where you get the bes...
t image quality, so I'm a hopeful person and if I was very pessimistic I'd set it at 6400, that might also be realistic too, but ideally I would like to have it at 100, whether it stays there, that's another issue. Next up, what's more important in this photograph, aperture or shutter speed? Well, I've already mentioned freezing motion, picking your battles, the most important battle here is freezing your motion. Now, how fast does an eagle move? I don't know, I'm not an eagle, I don't photograph eagles everyday, but I can bet that they're faster than humans, and so I know it's gonna be faster than 500, and it's probably notably faster so it's probably not just so it's gonna be up there in 1000th of a second and so, to be honest with you, a lot of times I'm just guessing 2000, 4000, okay, those are smart choices, smart guesses you might say. Now, when it comes to the aperture, there's a lot of different questions we can ask and one question is, how important is the background for this particular photograph? And there doesn't seem to be anything, maybe if there was a grizzly bear in the background we would want to have that info 'cause that would be interesting, or more eagles, or something else. But in this case, there's really nothing there, so for the aesthetic side of the issue, I would choose a very shallow depth of field. For just pure sharpness reasons, lenses are sharper at probably F8 or F11, but in this case, I like that shallow depth of field so that your eyes are right on the subject and the background is not a part of the story at all, it's all on the subject. So this is fantasy land. This is where you would like things to be. Let's take a look at reality, which is our light meter, in this case. And the light meter, in this case, says that we are three stops underexposed. As I mentioned before, three stops underexposed, you're gonna be way too dark, that is not right. We need to let in three stops of light. Now, think about aperture. Can we let in three stops of light with the aperture? No, we are maxed open on the aperture, it's at 4.0, so we cannot save the day with aperture. If we come over to shutter speed, we can open up shutter speed by three stops, we could go down to 1000, 500, and then 250th of a second. But if we go down to 250th of a second, it kinda destroys the whole thing that was important to this photograph in the beginning. And so, that's a way of solving the problem, but it creates a new problem. That's pretty significant. If we come over to ISO we can bump it up to 800, let's go ahead and do that now, and that solves the exposure issue, we still get the shutter speed we want, there is the slight difference of shooting at ISO 800 compared to ISO 100, and with pretty much all modern cameras, that's a pretty small difference. I would prefer to be at ISO 100, but I'm more than willing to accept 800. And so that's a good compromise in this particular scenario. So, hopefully that makes sense. I don't know if there's any questions on... And this process is something I'm going through very slowly here and it is something that, as you get out in the field, this starts becoming very intuitive and very, very quick. And is something like, well, how do you have time to do that with the eagle coming in to grab it out of there? There was, like, 10 of them up in the trees and they were coming down every 30 seconds, and so you get out there and you practice, and then you're ready for the big time. Alright, let's try this again with maximum depth of field. So we are in Ngorongoro Crater, Tanzania, and came across this unusual situation where we get really close to the zebra, and I wanted the one in the foreground, and then the midground, and then all of the ones in the background to be in focus. And so, I wanted lots and lots of depth of field, in this particular case. So let's take a look at our settings. I'm hopeful, so I'm gonna hope that we can get this at ISO 100. Now, think about what we want to set next. Where would you set it? Pick a number and see if it's where I happen to go with my choice. I wanted to maximize the depth of field. I want to get as much depth of field as possible. Now, the shutter speed is a bit of an issue because is there anything moving? Well, yeah, yeah those zebras might be moving around, and I might be moving around, 'cause I can't have a tripod in a vehicle, that doesn't do any good. And so, I need to be aware and careful about the shutter speed. I can't go too low on shutter speed, and so, my general philosophy on shutter speeds is, I said a 60th of a second is kind of safe for handholding, I like one extra for safety, then I know that there's barely ever gonna be a problem with handholding the camera. So, now we want to take a look at the light meter. And the light meter says, we are two stops underexposed. Okay, that's not too bad, two stops is reasonably close, but I need to let in two stops of light. Now I could do it with the aperture, but that would take away from what I'm trying to do in the photograph to begin with, the intention of the photograph. I could go down to a lower shutter speed and cross my fingers, just hold the camera as best I can and maybe I can get it, or I can bump the ISO up to 400 and get it. And of course, you can split the difference. You could do one with the shutter speed, and one with the ISO depending on what you determine you can do out there. And so, I was feeling like, okay, not too many people in the vehicle, I think I can get away at a 60th of a second, the zebras are pretty still, so they're not needing more, and then I was always trying to keep that ISO as low as possible. If I was careless, I would just bump it up to 400, or 800, and have an even faster shutter speed, but I'm always trying to maximize each little bit, so that you're as efficient as possible with it. Let's do one more. We're gonna do portrait photography. So, a lot of times in portrait photography, you want your subject in sharp focus and the background out of focus, especially in this case 'cause there's a very cluttered store that she's in, a lot of competing things in the background. So, ISO 100 gets you the best image quality off of the sensor, and in this case, I want to go with the shallowest depth of field I could. Now, it'd be perfectly acceptable to shoot this at two or 2.8, but I was trying to get the shallowest depth of field possible. Now, my rule for handholding is 60 plus one for safety, puts me up at 125th of a second, and if I can get this I'll be really happy, but life is never perfect, and so in this case I'm only one stop off, so I only need to change one stop. I'm too dark, I need to let in one stop of light. I cannot do it with the aperture because I'm already maxed out, right there, at 1.4. I can come down to a 60th of a second and as long as she's steady and I'm steady, it'll all work out quite nicely, if either one of us was moving around a little bit I would bump it up to ISO 200. Now, I specifically told her to put her arms on the table like that so she was not moving around as much, you see I'm a manipulator. (laughter) And so that way I could shoot it at a 60th of a second because I too had my elbows on the table and was able to support myself and hold the camera in a very steady position. And so that's how I got the exposure, in this case, and this is how you'll have to work every photo you take, if you take it manually is you're gonna, a little bit of bargaining and trading back and forth to get it dialed in and think about what the make or break issues are, whether it's depth of field or shutter speed with you, and you do what ever you can, and generally you're gonna have to bump up the ISO, and it's not ideal, but it's what you have to do in some cases. You just don't want to needlessly waste resources, your using either too fast a shutter speed or choosing an inappropriate aperture. So choose what's appropriate for the situation.