Now it does get a little confusing for people about, "Well, there's different size sensors," "and what's the normal lens" "and what's my telephoto lens?" And so what you generally want to be thinking about is what you have right there in the middle is a 50 millimeter lens for fullframe, and this would be slightly different for the different size sensors. Now with these lenses when you go from and you get progressively wider and wider angle, 35, 24, 16, and then when you go in the other direction of this, you'll be going up, and I'm just doubling the numbers for simplicity. 100, 200, 400, there are many options in between this and beyond this but we're just gonna try to keep it nice and simple in here. Now you may be wondering, how does this compare with what we see with our human eye? Well the human eye is a very different optical device, and it's a little hard to compare it but let me do my best here. And so the angle of view that we're gonna see with our eyes is determined by the re...
tina in our eyes which absorbs light and we can pick up information. Now the retina stretches around the back end of our eye and we can see stuff, not great detail, up to 150 degrees, and so if you put your hand way off to the side of your head, I can see right now that my hand is moving over here, now if I hold up something to read like the pdf for this class, I can't read it over here, it's not enough detail. I can see some color and I can see movement but it's not real detail. If I really want to look at it and read it I gotta look directly at it. And that's because in the back of your eye is the fovea, where you have really tightly packed rods and cones where you can see with great detail. And that's the equivalent roughly of about one degree of view of your vision, it's like a 2,500 millimeter lens, and that's what we're using when we read something. We have to look right at those words. It's very hard to read something if it's not directly in our line of sight. And so that's kind of a different lens, but then we also have our central retina which is an area on the retina that is tightly packed with rods and cones where we can see with great detail. And that's gonna give us an angle of view of roughly around 50 degrees, and what I often refer to this is this is our movie seating choice, where we like to go into a movie theater. Imagine walking into a movie theater, you can sit anywhere in the theater you want, where do you usually sit? Well we usually don't want to sit too close to the front because we gotta look back and forth, from side to side, you don't want to sit too far in back because then the screen's kind of small and far away. And so this is a nice happy medium area where you can have a good view of everything that's going on and you're not too close and you're not too far away. And so that's kind of our normal lens which is equivalent to a 38 millimeter lens on a fullframe camera. But we're not using our eyes to take photos, we're using a camera. So what's the normal angle of view on a camera? Well, it's been traditionally said that what you do is you take the diagonal of the sensor or film that you were using and the case of a fullframe camera, that is 43 millimeters, and a 43 millimeter lens would be considered a normal lens. If you have a cropped frame camera like a lot of the Canons and Nikons out there, Sonys, Fugis, that would mean that a 27 millimeter lens would be your normal lens that would give you a normal angle of view. Now there's not too many 43 millimeter lenses nor are there 27 millimeter lenses because they're kind of odd numbers, and so the other numbers that we have that are pretty close because in photography we like numbers that are kind of rounded off, nice even numbers. We have a 35 millimeter lens which is a little bit on the wide side. And then we have a 50 millimeter lens which is just a little bit on the telephoto side and it became the standard partly because a slightly telephoto lens was a little bit easier to manufacture than a wide angle lens. And so the normal lens on a fullframe camera is gonna be a 50 to 35 millimeter lens, and if you have a 1.5 crop lens, it's gonna be around a 30 to 35 millimeter lens, and if you have the micro four thirds system it's gonna be around that 20 to 25 millimeter lens range. The first big set of lenses that we're gonna look at are normal lenses. And so when we talk about a normal lens we're talking about a normal angle of view. For fullframe that's a 50 millimeter lens. For a crop from around a 35, and for the micro four thirds it's gonna be around a 25 millimeter lens. And so this is what you're gonna see from side to side about 40 degrees. And this is great when you have a good subject that you want to render very normal in its perspective. If you have essentially a good story, a good shot in front of you and you're not trying to manipulate it, you just want it to look as real as possible, then a 50 millimeter lens is a good choice. One of the advantages of the 50 millimeter prime or fixed lens is that it lets in a lot of light and allows you to shoot in low light situations and allows you to shoot with shallow depth of field, which we'll talk about in an upcoming section. And so anytime you want to be very faithful to your subject and show it in very much a straight photography, a photo journalistic standard, documentary standard, these normal lenses around or in this case 50 millimeters do a very good job. Shows you a very realistic size relationship of a foreground subject, a midground subject and a background subject, it's not playing deceptive games which I do like to do, but from time to time you want to tell a simple and clean straight story. The 50 millimeter lens is also a very good people photography lens. Now it's not quite what I would call a great portrait lens for doing closeup portraits, but for generally photographing people I think a 50 millimeter lens does a good job because it renders people and their perspectives in a very normal fashion. There's a lot of street photographers and travel photographers that love the 50 millimeter lens because it's very honest and real and it's not deceptive and it really portrays the world very much the way we see it with our own eyes. And so when people look at a photograph they're not gonna say, "Wow, how big was this?" or, "How small was that?" It just looks very, very natural and so it's great lens and it's one of the best lenses for somebody to learn photography on. The next choice of lens is also what I would call a normal lens but this is a little bit more on the wide angle side, so this is what I would consider a modestly wide angle lens, and this lens is probably the most popular lens ever made as far as the different size sensors and the angle of view that you see from this. This is what a lot of the phones have on them, but recently I'll be honest, the phones have been getting a little bit wider angle, they've been wanting to accommodate for this thing called the selfie so that you can get more than one person in the shot. But this is a very, very normal lens that we've seen on many disposable cameras and any camera that had just a single lens probably had something pretty close to a 35 millimeter lens. Now this is like the 50 millimeter lens in that it's very honest and truthful about the way it shows things and the perspective and the size relationships. It's a very popular lens for travel and street photographers. It's really good for environmental portraits where you want to show a person and a little bit of their environment around them. It may not be good for a tight head shot because you tend to be a little bit too close and the perspective doesn't look quite right. But for an environmental portrait of people it's a really good lens, so it's a very good documentary lens, photojournalist style lens. And it's just kind of the start of where a lot of landscape photographers like to be when they are telling a wide angle story where they want to show the larger environment around them. One of the things that's nice about these 35 millimeter lenses is that many of them including the prime lenses, the fixed lenses, is that they allow you to focus very close and so you can have a subject in the foreground and a subject in the background as well, and they tend to be just very, very practical lenses. I've seen a lot of polls from photographers and asking them what would be your desert island lens? And when it comes prime lens that does not zoom, most people would choose a 35 millimeter lens because it's probably one of the most practical lenses you can have for doing anything general. Now tell me what I'm gonna shoot specifically and I may have another choice very, very quickly, but if you said, "Not gonna tell you what you're gonna shoot," "I just want you to be ready with one lens." The 35 would probably be the safest choice that you could make. So the two lenses we talked about in this section are the 50 millimeter lens and the 35 millimeter lens. Remember technically for fullframe the normal lens is a 43 millimeter lens which is pretty much right in the middle, so we have one that's just a little bit telephoto and another one that's a little bit wide angle. So very similar angle of view to our own eyes, now it's not exactly the same as we see from side to side because we do move our eyes around, but it's gonna render a normal or standard perspective, and it really emphasizes the subject and not the process, and if you were a photography instructor and you wanted to force your students to really learn the practice of photography, you give them a 50 millimeter lens and say, "That's all you have to play with," and that's what happened to me in my class is that I could only use a 50 millimeter lens, and when you're forced to only use a 50 millimeter lens you start concentrating on everything else that really matters in photography rather than deciding, "Oh I'm just gonna play around" "with different things to make them look differently." Forces you to really work within a narrow perspective and can be really good for you, and so it's a good little tip if you want to go out and shoot and just kind of have a learning exercise, just take a 35 or a 50 millimeter lens out there and have the whole day simple, lightweight, one lens on the body, and see what you can find and shoot with that.