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Lesson Info

Focus Overview

We spent the last few sections going through the camera, the shutter speed, the aperture, really nailing the exposure, and now it's time to move on to a different subject, focusing. And the sections before have mostly been dealing with getting the correct amount of light in our camera, also getting the right look of the image, and the focusing section is really critical because that's probably the number one reason why, at least I, delete photos. It's because they're not perfectly focused, and if they're not perfectly focused, they're pretty much throwaways, and so it's something you have to get right in the field. You can't just say, well, I'll fix that later. You gotta get it right in the field, and there's a lotta things goin' on, and so that's what we're gonna be spending this section on. Before we get into this section, I wanna just talk about somethin' else a little fun, okay? And I often see a lot of photographers write things, have videos, and there's a lot of photographers tha...

t get mad at other photographers for what they take photos of, which makes, really, no sense to me. And it's along the lines of the photo cliche, oh, say, flowers. Don't take picture of flowers, everybody's taking pictures of flowers. What about pets? Stop taking pictures of your pets, everybody's seen picture of pets. Folks, the fact of the matter is is that everything has been shot, and if you decide to only shoot things that no one has ever shot before, you're gonna have a very short list of things to take photos of, and so despite what people say about stop taking photos like these, well the selfie one, that one I can actually understand a little bit, that one, we might need to cool it on that one, folks, just a little bit on that one, I'll have to say. But there are so many things that everyone else has shot, you should not really care what anyone else has done. We all need to go down our own photographic path, and it doesn't matter if somebody else has been to a location 100 times, feel free, go there, shoot your own photos, follow your own path. What you will probably find is that if you continue to shoot one subject over and over again, either you're gonna get tired of it, or you're gonna become the world's greatest expert in that, and that's how you're gonna make your living, and so follow whatever your heart desires in what you wanna shoot, and it will take you down its own natural path, and don't let other people direct you to what you should and should not do if this is something that you're doing for your enjoyment and pleasure of photography. So forget about all those photo cliches, do whatever you want. Okay. Let's get into the section on focus. We've got a lot of things to talk about, so we're gonna keep moving through this. The first thing is as I just mentioned, is that you have to nail focus. There is no comeback to a bad focused photo. If you don't get the depth of field right, if you're shaking the camera, if it's blurry for some reason, there is nothing that you can do. There is theoretical things that people are talking about on how to make a picture sharp again, and we've seen movies, we've seen it in TV shows where the detectives are looking at the information, the CSI, can you sharpen this up? Let's go a little sharper, zoom in, now sharpen, sharpen, sharpen, and I really don't know how they're going to do it. For instance, if I am completely out of focus, and my shirt is this gigantic blob of color, and I have buttons on my shirt, how are you gonna pick out buttons when there's no detail for those buttons to see how many holes are in the buttons? I don't know how that would work, maybe someday we'll have software that allows to refocus out of focus images, it would be fantastic, it would save a bunch of photos of mine, but it doesn't exist now, nor do I see it in the near-time future, so this is something you have got to nail down. Most of us are using autofocus lenses, and I do not have a problem with autofocus at all. I do like manually taking control of my camera. I wanna be the one making decision what I'm focusing on, and if it's changing or not, the depth of field, I wanna be in total control. The autofocus on cameras is simply an assist, a help. It can focus faster, and more accurately than I can with my own eyes. So for a couple of the more common systems, Canon it's very easy. If your lens has autofocus, there's gonna be a switch right on that lens, and you can leave that in autofocus most of the time, I think you're gonna be fine there. Nikons, a little bit more complicated. In the earlier Nikons, they had the autofocus switch on the body, so if you had an older pre-digital Nikon for instance, there was just a switch on the body, but now on their newer lenses, they're putting a focusing switch on the lens, and so if you have a Nikon camera, my general recommendation is to leave the autofocus on on the camera body 100% of the time, and if you do wanna manually focus, switch the lens switch back and forth to manual focus and autofocus, and that seems to be the direction they're going with all their newer equipment. One of the things that you will notice about the Nikons is that some of the more basic lenses have a very simple A for automatic focus, and M for manual focus, pretty clear as to where you'd wanna put that. Some of their lenses will have a slightly different lettering code, which is M/A, which means that if you want to manually override the autofocus, you can by simply grabbing the lens and turning it, it's got a special clutch override so that you're not burning motors or causing any problems. On the more basic Nikon lenses, if you turn the focusing ring, it doesn't feel very smooth. It's got a really rough, and it kinda locks in. You should not try to manually focus the lens, because the focusing gears are tied in to the actual lenses that are moving, and so there's a special focusing clutch down here which allows you to do the manual override, which is a common feature both in Canon and Nikon lenses, is that their higher end lenses, you can just grab and manually focus if you want to. But there's a number of other controls you need to know about on the camera, but those are the most basic ones to first start off with. There is a number of lenses from both Canon, Nikon, and other manufacturers that will have focusing limiters on them, and so you should definitely check this to see if it's on your camera, because you may not be able to focus on what you intend to if this is in the wrong position. So in this case, let's imagine your camera is focused on a field out in front of you, and looking at the Nikon, or excuse me, the Canon adaptor on the top, if you set it to Full, it'll be able to focus from two meters to infinity, so that's where you would probably leave it most of the time. There is an option to focus only between two meters and six meters, and so you would only be doing this if you are focusing on close up, perhaps if you were doing portrait photography, and the person wasn't too far away from you. The mode that it's mainly intended for is six meters to infinity, and this would be people who are shooting sports photography who know that they are not going to be shooting somebody right next to them, they're well behind the lines of where the athletes are, and if the lens is limited to this range, the lens will not try to come down and focus where there is unlikely to be any action, and so what it does is it shortens up the time the camera is looking for focus, which means it'll achieve focus faster. So doing sports photography, the six meters to infinity would normally be a good place to put it. Under normal shooting conditions, you can just leave it in the full position, and I guess there's a few special situations where it might be in that shorter position. But you have to take a look on your lens. This is something you'll typically only find on telephoto lenses. It's really nice if your lens has a distance scale on it so you can see where the lens is being focused at. Not all lenses have this, I think the better quality ones do. With the mirrorless cameras, a lot of times this information is provided in the viewfinder, depending on the system that you have, it may or may not have this, but this is the sign of a more serious photographic system that has this extra information on it. So let's talk a little bit about this focusing scale. They'll usually have it in feet and meters, so you can work on whichever number scale you like. As the lenses in your lens move away from the camera body, you're focusing closer up, and so it's kinda the opposite of what you might think. And as you focus to infinity, all the lens elements move back into the camera body, so the infinity position is generally the normal or standard position on your lenses, if you're kinda wondering where were they tested at for sharpness, where they just naturally want to be, and that would be in the infinity setting. So one of the things to be aware of, and this is really important for anyone who wants to do star point nighttime photography, is that most lenses, good working lenses, can focus beyond infinity. So there'll be a mark for infinity, and you can focus a little past that, and that is to leave a little bit of leeway room for heat and cold expansion of the lens. In some cases, the tolerances change ever so slightly, and so you wanna be able to focus slightly beyond infinity, and where this becomes a problem is if you're doing night photography, and you have a hard time focusing, so you just rack your lens all the way to one side, thinking it's infinity, it's really beyond infinity, and now all of your stars are slightly out of focus. Just as a side note, I was looking at a used lens to buy a couple weeks ago, and I was checking the lens out, and it was a manual focus lens, and it focused right up to infinity and it stopped right at infinity, and I ended up not buying the lens because I knew that that's not the way it's supposed to be, you're supposed to be able to focus a little beyond infinity, and I don't know, if the temperature drops 20 degrees, for some reason, I may not be able to get that lens to focus on infinity, and so you should have a little bit of overlap at the end for that reason. On a variety of lenses, not all of them, some of them will also have infrared focusing marks on them. Many of the Canons do, only a few of the Nikons do, very few of the other manufacturers have that, and so if you are doing infrared photography, which we're not gonna get into in this class, they will have special marks because those, when you do infrared photography, you have to focus your lens at a slightly different place because the infrared light has a slightly different wavelength and focuses different than the visible light, so be aware that's what those extra markings might be for. One of the surest ways to make sure that you got sharp focus is to play your image back and look at it, and so make sure that you know where the magnification symbol is on your camera because all digital cameras allow you to play an image back, zoom in, and kind of move around to see if it is sharp in focus. And as I mentioned in the first section of this entire class, this is where mirrorless cameras have a distinct advantage, is that it is easier to check this magnification because you can use the eye-level viewfinder in bright light, or if your own eyes can't focus close enough, on the back of the screen. But this is a great way to check to make sure on any really important situation, did I actually get it focused correctly? Seeing the results is very very helpful, so make sure you know how to do that on your camera. SLRs use a system called phase detection focusing. So we're talking about all the Canons, well not all the Canons, but Canons and Nikons that are SLR in style, the ones that have a mirror on it have a specially designed mirror. It has a partially silvered middle area of the mirror and this lets light through that mirror. So part of the light is bouncing up to your eye, part of the light is going directly through this mirror, and the reason it goes through that mirror is for a couple of reasons. One, the mirroring system that we talked about in a previous section, but there is also light that comes down to the autofocusing sensor in your camera. This is how when you hold the camera up to your eye, the camera can focus, and it knows what you're pointing the camera at, because it's looking at exactly the same thing. Now this autofocusing sensor, we can see in this diagram as well, light goes through the mirror, bounces down to the autofocus module on the bottom of the camera. Now the way this phase detection focusing works is that it is looking for lines of information, so it works very good with horizontal and vertical lines, and so as the light goes through down to the mirror, the focusing beam splitter down here can tell if that vertical line is lined up or not with its two-piece vertical line sensor, and if it's not lined up, it directs the lens on how to get the best focus. Sometimes the sensors are designated to look simply for horizontal lines, and so that light goes through to the beam splitter, and it can tell if the horizontal line is correctly focused or not, and if it's not, it turns the lens and it becomes a continuous line on the horizontal line sensor. And so that's what's going on behind the scenes, and the important thing to know is that SLRs really like horizontal lines and vertical lines. And so we're gonna talk more about this as we get into the focusing points, but that's what you need to be pointing the focusing points of your camera at. Now, some cameras can get very complicated with the way their focusing systems work. I'm just gonna show you one camera as an example of what can happen on some cameras. This is the Canon 5DSR, which has the same focusing system as the Canon 5D Mark III, and so it has, I'm forgetting off the top of my head, I think it's 61 focusing points, and these ones that I have outlined in green here, they work as horizontal line focusing points, so they can only sense horizontal lines, and the 5.6 part of this means you need a lens that has a maximum aperture of 5.6. Now, lucky for us, all of Canon lenses are 5.6 or better, so this means it works with all Canon lenses, but it only works in a horizontal line format. The next group that you see in red here, these work 5.6 horizontal line focusing just as the others, but these also work as a vertical line focusing, but you need to have a lens that is F/4 or faster, which is what I would call their professional, semi-professional line of lenses. As we go up to the next group of them, that middle three rows, these are F/5.6 cross-type. So 5.6 means they work on all of the Canon lenses, cross-type means they work with horizontal and vertical lines, so this is the best type of line so far, 'cause it's the most versatile. And the actual best are the five ones in the middle, which are a dual 2.8 dual cross-type. Now, these only work with lenses that are F/2.8 or faster, so if you have a 70 to 200 F/4, they're not doing anything for you. The dual cross-type means that not only are they looking for horizontal and vertical lines, they're looking for lines that are at 45 degree angles as well, so they're just super highly sensitive, and these will only work with those faster lenses. And so, Nikon is a little different, and Sony's a little different. The mirrorless cameras are very different than this, this is just the SLRs. But this just shows you how complicated, and what's happening is that Canon would like to put F/5.6 cross-type sensors in the whole area, it costs more money, and it's technically very challenging, and this is what they have in this one. Some newer cameras, Nikon just introduced a couple of newer cameras that have some very nice focusing systems that have expanded on some of these capabilities, but that's one of the reasons that you wanna really learn about your camera's capabilities. That's something I go through in my individual fast start classes, as to what type of focusing system you have in your camera. It's good to be aware of for anyone who does a lot of action photography.