all right. It is time to move on to the aperture within the lens. And so in your lands is an aperture that is gonna be able to give us some control over the amount of light coming in to the sensor. So this is the opening through which light travels. Now I have found that the word aperture gets used in some incorrect ways much of the time, and people will ask you about what apertures that lens you have. And that's actually incorrect. That they're trying to ask you is what's the maximum aperture of that lens you have? Because the maximum aperture is listed there. It's that 1. formula in this particular case, when they ask about the aperture that is really the mechanical device in the lens that opens and closes. All right, diaphragm Iris has a lot of different names that it could go by. And so with this, the focal stop, the ratio the focal length to the lens to the entrance people. So this is the size of the opening that were shooting. And so this is a good graphic for you to memorize. Al...
l right, That's why we have it up on the wall in here right now. It's a very important concept to remember because these are fractions and it's kind of awkward because 1.4, which is a small number, is a big opening in 22 is a small opening, but it's a big number, relatively speaking. So let's go ahead and take our aperture and start closing it down. So as we close our aperture down with each one of these settings were letting in half assed much light. So these are very important increments, and as we open up our aperture, we're letting in twice as much light. So it's very much like shutter speeds and that we're gonna be trading these numbers back and forth. Well, maybe I should do this with the shutter speed and this with the aperture, and everything will be equal, just kind of trading them one for the other. And so 1.4 wide open, 22 very small. So if we go from 5.6 toe f four, we are opening up the aperture by a full stop. We're letting in twice as much like if we go from 562 F aid were stopping it down and letting in half assed much light. And this is where things are a little bit different than they were with shutter speeds and I esos if you remember back to shutter speeds and I esos we were doubling the numbers and we were cutting them in half. Not so here. In this case. We're going from 562 F four and we double the amount of light. And that's because with a circle, well, that's kind of has unusual properties. You only have to make a circle a little bit bigger to double the surface area of that. And so that's why we have this kind of odd set of numbers that you need to know about in photography and these air, the kind of the prime aperture numbers that you will see listed for lenses and settings on your camera. Now, some people with these zoom lenses, as we're talking about with variable apertures, get a little confused because they go. I got the 16 80 lands. It has a range of two A to F four. Does that mean I only get to use two apertures to wait in f four cause it kind of sounds like to eight Dash F four. That's the range that you have. Know what that means is it means it 16 millimeters. You're gonna be able to have a maximum aperture of 2.8. All right, but you will be able to stop your lens down. Probably two F 22 or maybe beyond. When you zoom it out to 80 your maximum aperture is at four and you'll be able to stop it down to 20 to 32 or maybe beyond. And so it's just listing what the maximum aperture is. It's not listening. The range of the app. ITunes. So when you see that listed on your lands, it's just one part of the equation. But it's the important part of the equation. Usually, we're not checking to see how far down are lenses can stop, although that can be a factor for some people who do need lots of depth of field. But generally lenses are going to stop down more than enough for what everybody needs. It's the other end. That's the really important. Alright, this might be the least favorite slide in my entire classes. I want you to memorize all the aperture settings. Does anyone fear feel now? Like they could just rattle off all the aperture settings? Raise your hand if you think you could just rate rattle off all the aperture settings Nobody it like if I had to write down on a piece of paper. Okay, well, let me let me give you some hints on how to do it. If you can remember two numbers, you can figure out the whole sequence. The first number is number one, and that's so easy That doesn't take any effort at all. So the only need to remember the next number in the sequence, which is 1.4 now, the way that you figure out the whole formula is you take a number and you double it for the following number. And so, if you're at a certain number, you just look to the previous number. You double it, and that becomes your next number. So every other number doubles. All right, Do you see the sequence here? So if you could remember one in 1.4, you could figure it out as far as you need to go. So let's go ahead and take this out a little bit further. Here, do the math, right? Is your seen it on screen? What's the next number gonna be now? Yes, Every once in a while, we do round a number up just for simplicity sake. And you could keep taking this on into infinity. So remember, one and 1.4 and what's special about 1.4? It is thes square root of two. Okay, that's a faras. We'll go into that. All right, but this is the serious remember one in 1.4. Now, let's see who's can answer this tricky question in the class. So if we Well, there's actually a story about this, Uh, has you fell? Heard of the movie directly, Stanley? Cuba. Rick, Right. Well, he produced a movie called Barry Lyndon and in very lended he waas filming some really, really low light seats. And he needed the fastest lenses he could find now the fastest lenses he could find or so special Zeiss lenses that were made, I believe, for the NASA program. All right. And so he got his hands on one or two of these lenses. We could film this really low light scenes and the lens that he got was one stop faster than a one point. Oh, let's my question to somebody in the audience. Here is what was the Apertura that lands? It's a stop faster than a one point Olin's. If you know, raise your hand and will pass up. Let's get the microphone up here. It's half of 1.4. Okay, so what's half of 1.4? Thank you. 0.7. All right, So everybody, check your closets. Check your basements. Your attics. See, if you have a Carl Zeiss plane are 50 millimeter f 0. lens and it's gonna be worth Mitar, right? There's only like, six of these things made on. And so, yes, you can have lenses faster than one point. Oh, it just happens to be a relation of ah, 51.0 lenses a 50 millimeter lens with a 50 millimeter opening. With this, I have to run the math, but it's gonna be some millimeters in its opening. And so it's a difficult, challenging lens to make, but it is possible, and so you can go to really almost infinity in either direction on this as far as you want. And so just remember, one in 1.4 and you've got him all memorized. Now, how many people in this audience could figure out all the apertures? Raise your hand. Okay. I was hoping to see everyone's hand. Good, because it's really easy once you know the secret formula. All right, So the apertures that you're gonna be using in the real world of photography for the most part are gonna range from 1.42 F 22 now, like cheddar speeds and the ISOS. We're gonna be able to select third stops if we want. So if you want to get very precise or you need just a little bit more depth of field where you're tryingto balance some other part of the equation feel free to set these third certain thirds of stops. There's no problem with them. I'm just not gonna list them because they cut her up my screen with too many numbers. We're going to stick with the whole members, so these apertures are going to control the amount of light coming through the lens. But they do something else. That is quite interesting and makes photography a lot of fun, and that is it controls the depth of field. And this is what we're gonna talk about in the next section.