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Focal Length: Angle of View

Let's move right into angle of view. So, when we talk about angle of view, there's a number of different ways that we can measure what we are talking about. And so, as you look through your camera, you could measure diagonally, which is a way a lot of manufacturers will rank their lenses and grade them. You could measure it vertically, but I think most people, because they just hold a camera horizontally, very easily to conceptualize what it means horizontally do you get through a camera from side to side, so that's the terminology that I like to use. So, this is my favorite place to go shoot different focal lengths, it's this road leading down to Monument Valley, and I'm gonna be shooting this with a full frame camera, and you will see the focal lengths on the top of the frame. Now, I know a lot of people in my class don't have full frame cameras, and so, if you wanna kinda keep check, over on the right hand side of the frame, for those of you that have a crop frame, for instance, a C...

anon Rebel or a Nikon D5500, a lot of different cameras have this little crop frame of 1.5 or 1.6. And, you can see over in the blue what the equivalent focal length is, and so, if you were to go and stand out in the middle of this road, which it's not safe to do for a long period of time 'cause there's a lot of cars on it, and put a 50 millimeter lens, this is what it looks like. It's a very natural perspective as far as the relationship between the foreground and the background, it mimics the way that our own eyes see. For the crop frame users, you need a 35 to achieve a similar result. So, what we're gonna do is we're gonna work our way down to the wide angle end. For the technical people out there, over on the left I'm gonna show you the exact angle of view in case you wanted to know what it is. And so, here we are at 35, it's just a slight difference, a little bit wider angle, what we would call a moderate wide angle lens. So, keeping the camera in the same position, zooming down to a 24, we're getting down to the range of a real nice wide angle lens. So, we're gonna start moving into the ultra wide territory, down to a 16 millimeter lens, and one of the things you'll notice as we get down to this really wide area is notice the foreground road here, look at how much of the picture this takes up, it's really taking up a quite large portion of the entire frame. And, the widest lens currently on the market for a full frame camera is an 11 millimeter lens, and so you can look at how much this road and this one little stripe here is taking up almost a quarter of the frame vertically. And so, that's as wide as we get, and this 11 millimeter lens is 117 degrees across, and 126 degrees from corner to corner, it's a pretty ridiculously wide lens. All right, and in here we can kinda crop in and see where we were at 16, 24, 35, and 50. And so, I've always wanted a pair of glasses that were completely clear but they had the frame lines, and so I could just kinda click on the frames lines so that I could see what lens I need for a particular subject. All right, so we're gonna zoom our way back up to 50, and then go into the telephoto. And, just as a real side note as we're zooming back up, this was a very difficult series of photos for me to shoot, because there were so many other photographers stopping and standing out in the street, and I didn't want them in my photographs. I had to wait two days to get these total shots. Okay, we're up here at 100, so now we're in the telephoto range, and we often talk about zooming in and bringing our subject closer, and we're not bringing the subject closer, but we are magnifying the subject. And, one of the effects that we get as we zoom in, 200 up to 400, is we're getting a compression effect. Compression happens when you have multiple subjects, and let's go all the way up to just to make this as extreme as possible. And so, compression effect would be the car on the road, just about to head around the bend here, and the butte in the background, those are two separate subjects, and we are compressing and making them look closer together. Now, I had shot a previous series that I've used in previous classes, and I just kind of recalling off of my mind how far was it from that bend in the road to the butte in the background, and I told everyone it was about a mile. Well, I went back to reshoot this with new wider angle lenses and stuff, and I realized that I was a little bit off, it's actually five miles from that car to the base of that butte, and that is a real good example of compression, so that's a big difference there. So, let's go ahead and bring it back down to 50 here. And so, there's a number of reasons why you're gonna wanna choose lenses, and compression might be one of them. And so, as we come back down to 50, this is once again what we're gonna see relatively with our normal eyes. Now, our eyes work very differently than cameras, and we have the ability to turn our heads and turn our eyes, and so we do get to see more from side to side, but the size relationship is accurate at around 50. And here, you can see the cropped in lines where we would be at 100, 200, 400, and 800 millimeters, so I think is just kind of a nice little reference, how much are you getting with each lens. So, the angle of view, 50 millimeter lens sees about this from side to side, and we're just looking at the same thing from above, so our wide angles, our ultra wides, and incredibly wides, and then we have our telephotos. And so, I remember I was in college, I had one of these that I got from a brochure of a camera up on my wall, 'cause I just kinda wanted to learn this and really have this ingrained in my brain. And so, we have on top the full frame sensors, and on bottom the crop frame sensors, the equivalent focal length, they're gonna give you a similar angle of view. Now, one of the questions that I'm thinking of right now, and I don't have the answer for, but I'll ask the question, is if I own the crop frame sensor, should I think in terms of full frame or not? Because you have to be able to translate things, and so it's kinda like the metric and the imperial system, and so if you're American and you're used to miles and you go to Europe and all you see is kilometers, you gotta be able to figure how to click that over and one mile equals, you know, 1.2 kilometers, or two kilometers, or whatever the exact number is. And so, if you are using a crop frame sensor, you can kinda have your own numbers that you keep in your own mind, but when you read articles and you hear everyone else talking, you better be able to translate those over to what everyone else is talking about. So, what does the human eye see? Well, the human eye is a very unique device, and it's very versatile, very adaptable. Now, we see because light comes in through the iris of our lens, and goes to the retina. Now, the retina covers a large portion on the back of the eye, and so light coming in from all different angles, I mean, I can see from over here, over here, without even turning my head. Now, I don't have real good vision, I can't read a book over here, but I can just see somethings going on over there. And so, we have this huge wide angle view through our eyes. To really see sharpness, we use the fovea, which is a highly densed, packed area of rods and cones in our eyes so that we can see in detail, which is the equivalent of about a one degree angle of view. And, if you think about how you read on a page, you have to look at that exact word, you can't look at the other side of the page, you have to look exactly where you want to read because you're trying to see the detail in that area. And so, we have both a wide angle and a telephoto lens in some ways in our eyes. The rods and cones in our eyes get more densely packed as they get closer to the fovea, and so when you go to a movie theater, everyone kind of has favorite seats in movie theaters. Some people like to sit a little closer, and some people like to sit a little further back, you all know where I'm talking about, right? Well, it's my opinion that your central retina is covering an area that you probably like to sit in a movie theater, you know, it's just kinda where you can sit and absorb a scene in front of you without having to turn your head from side to side where you can take it all in. And so, this is your movie seating distance right here, so that you can sit there comfortably and not have to move your head back and forth, and not have it too small either, it's that perfect balance. So, how does this compare with cameras? Well, this is the equivalent, roughly, of a 38 millimeter lens. Now, obviously, being humans, we're all a little different, and so this number's gonna be different for everyone. I don't know how much it fluctuates, but it is a little different for everyone. And so, when figuring out what a normal lens is, there's a couple of different ways that we can look at things. One way that has been done in the past is to take the diagonal of the sensor size, which is very close to 38, it's 43 millimeters. Remember, if we talked about this back in the sensor section as well as being a normal lens, and so 43 is a pretty good number for a normal lens. Now, for those of you with the crop frame sensor, that's gonna be about a 28, maybe a 27, depends on which size sensor you have. But, we like to round things off, we love numbers that end in zero, it's just really nice. And so, we've kind of, ah, we'll just call it 50, that's like the next good solid number, you know, that seems like a really good solid number, and so that's how we've ended up with 50 as a normal lens. But to be honest with you, I consider the 35 a very normal lens, it's just a little bit on the wide side, and so both 35 and 50 are normal. What's exactly normal? Well, it's a little bit different for everyone, but it's somewhere in that range, and so that's what we mean by a normal lens or a standard lens. So, let's talk about the normal or standard lens. In most cases, we are going to be talking about the 50 millimeter lens, or the 35 for the crop frame. And by the way, for those of you with Panasonic and Olympus who have the micro four thirds system, you take the full frame and divide it by two, so the math is very easy for you folks. So, 40 degree angle of view, why am I gonna use a 40 millimeter lens? There's a number of characteristics about this lens. Well, it's a normal angle of view, and so if you have what I think is a relatively simple subject and you want to render it very natural, you don't wanna play any optical games with it, the 50 millimeter lens is really nice. And, a lot of the 50s are, well, they're just 50s, they're just a single focal length, and it's kinda nice to have a subject that you could walk up a little closer to and move a little bit away from. And so, you know, for me, I just wanted this to be as natural as possible, I didn't really have a second subject, it's just basically the bench, and the light pole I didn't have a second subject to compress, and if I shot wide angle then you would start seeing stuff that I didn't want you to see in there, and so the 50 millimeter lens was just natural for this, in my opinion. Woops, let's see if I can jump back here. So, the 50 millimeter lens was really nice in this case because if you get just a 50, they often let in more light, and that's kind of our next subject, but a lot of you know what I'm talking about, it's a 50 millimeter lens that does better under low light conditions, and so if it's getting dark out and I still wanna shoot pictures with a reasonable shutter speed where there's not a lot of blur, that 50 millimeter 1.8 or 1.4 is a fantastic lens. One of the other nice things about those 50 one eights and one fours, for instance, is that you can shoot with very shallow depth of field. You can have one subject in focus, and the other subjects, as they get further away, are more out of focus. And this is a really valuable tool to have, having that shallow depth of field. Now, that's a whole other subject that we're gonna get to in a moment, but good to talk about it here. 50 millimeter also works nice for people photography, it's not the classic head and shoulders portrait lens, we'll get to that in a little bit, but for general people photography, it's a natural perspective to see them in. I tend not to wanna shoot too tight, so I'm not gonna do like a tight headshot with a 50, but it's a very good, natural lens, because you can get that shallow depth of field, and it leaves all the proportions of the face and body very naturally as we would see it ourselves. And so, it's a very versatile, good focal length to use. Next up, let's talk about the 35, which is kinda the wide normal lens as I like to call it sometimes. And so, this is nice when you want to show a little bit more of the scene around you, or you wanna be a little bit closer to your subject. And so, this is one of the most popular focal lengths that you'll find, in fact, it is, in my opinion, without a doubt, I have no scientific proof, without a doubt the most common lens, and that's because virtually all the phones and mobile devices that are being used use a lens of around this focal length. Some phones or devices are slightly wider than this, but this is about as common as you get. For those of us who remember the disposable cameras, virtually all of those had a 35 millimeter lens or something really close to it. One of the nice things about many of the 35s that are out there is that you can still focus pretty close. And so, we can have a subject in focus in the foreground, but still include other subjects a little bit because it's still a somewhat wide angle lens. And so, it's a good general purpose lens, very much in the same vain as the 50 millimeter lens. And so, sometimes simple subjects work perfectly fine with a simple lens. So, the normal lens, some thoughts on using things in the 35 to 50 millimeter focal range. So, it's similar angle of view to our own eyes, so if it just looks good to you naturally without any thought about changing it around, that might be a good place to start. Standard or normal perspective, as we've been talking about. A good working space, that's where we have a little bit of space to move forward and back, and so, if I was photographing this table here, if this was something that I wanted to photograph and I have a 50 millimeter lens, well, depending on exactly the size of that table, it's kinda nice to be able to walk up a few steps, or maybe I need a few steps to move back 'cause I want a little bit more space on the side. And so, a 50 millimeter lens would be a terrible lens to have in, for instance, Yellowstone National Park, they have these walkways, and you have to stay on the boardwalk. And if you wanna shoot something over there, you can't step over into all the hot water and stuff 'cause you'll ruin it, and so you have to stay right here. And so, in places where you're kinda restricted where you can stand, fixed focal lengths can be very tough to work with unless you've already scouted it out and you know exactly the lens you need. All right, finally, emphasizes the subject and not the process. I love playing tricks, I love using super telephotos and wide angle lenses, but you know, when I have just a really good subject that's compelling and interesting on its own, I don't need to add anything to it, all I need to do is just document it, and that's what these normal lenses are really good for.