Skip to main content

Aperture: Maximum Aperture

Lesson 10 from: Canon Lenses: The Complete Guide

John Greengo

Aperture: Maximum Aperture

Lesson 10 from: Canon Lenses: The Complete Guide

John Greengo

buy this class


Sale Ends Soon!

starting under


Unlock this classplus 2200+ more >

Lesson Info

10. Aperture: Maximum Aperture


Class Trailer

Class Introduction


Canon Lens Basics


Focal Length: Angle of View


Focal Length: Normal Lenses


Focal Length: Wide Angle Lenses


Focal Length: Telephoto Lens


Focal Length Rule of Thumb


Field of View


Aperture Basics


Aperture: Maximum Aperture


Aperture: Equivalent Focal Length


Aperture: Depth of Field


Aperture: Maximum Sharpness


Aperture: Starburst Effect


Aperture: Flare


Aperture: Hyperfocal Distance


Camera Mount System


Canon Lens Compatibility


Canon Lens Design


Canon Lens Composition


Canon Lens Shape


Canon Lens Coating


Canon Lens Focusing


Lens Autofocus


Canon Lens Image Stabilization


Canon L Lenses


Image Quality


Canon Zoom Lenses: Standard


Canon Super Zooms


Canon Wide Zooms


Canon Telephoto Zooms


Prime Lens: Normal Lenses


Prime Lens: Moderate Wide


Prime Lens: Wide Angle


Prime Lens: Ultra-Wide


Prime Lens: Short Telephoto


Prime Lens: Medium Telephoto


Prime Lens: Super Telephoto


3rd Party Lenses Overview


3rd Party Prime Lenses


3rd Party Zoom Lenses


Lens Accessories: Filters


Lens Accessories: Lens Hoods


Lens Accessories: Tripod Mount


Lens Accessories: Extension Tubes


Lens Accessories: Extenders


Macro Lens: Reproduction Ratio


Macro Lens: Technique and Choices


Fisheye: Technique and Choices


Tilt Shift: Techniques and Choices


Make a Lens System Choice


Choosing A Portrait Lens


Choosing A Sports Lens


Choosing A Landscape Lens


Best Lenses for You


Lens Maintenance


Buying and Selling Lens


What is John Greengo's Favorite Lens?


Lesson Info

Aperture: Maximum Aperture

so I want to talk next about the maximum aperture. It's kind of leading into this whole section. So the maximum aperture is that critical factor that photographers know by heart about all their lenses. 1.4. So there's one a colon, and then a one point for its the 1.4 that we're concentrating on the one and the colon or just kind of setting us up for the right number. And so that is what is known as a fixed aperture. That's one single number, and you're gonna get this on prime lenses. Now, a lot of your zoom lenses have a variable aperture. So as you zoom the lens, in this case, from 10 to 22 it's gonna vary from 3.5 to 4.5, which can be, ah, little confusing. If you're setting your camera manually and you zoom, and all of a sudden something changes and it changes the amount of light that you are letting in and so serious photographers tend to avoid these. But having said that, a lot of serious photographers own these lenses because, well, that's the only way those lenses are made. This...

is a zoom lands with a fixed map maximum aperture, which means you can use this lens at F four at 24 at 70 and everywhere in between. You can also close the lens down to 56 and 8 11 support. This is Onley, referring to the maximum number I know some people get confused and they like the range of the aperture is 3.5 to 4.5. No, no, no, no, no, no. That is the maximum aperture that various back and forth you'll be able to stop this lounge lens down to 11 16 22 maybe even at 32 depends on lens. That's just the maximum opening, but very important. Number two. No on all of your lenses. So what is this? 50 millimeter? One colon? One point for What does that really mean? Because this looks a little like math and math is confusing, and nobody knows what math does. Well, at least I don't. I never did well in math, but I learned math because it's important and photography. So the one means it's a fraction. It's 1/1 0.4, and the one is whatever focal length this is put that number over the number on the other side of the colon, and so this case, it's a 50 millimeter lens. What's the focal length of this lends 50. All right, then let's put 50/1 500.4. And since we have a very small little area to write this, we're trying to do it in one line, which is why we use this slash or the colon. It means to divide by, So we're going to divide by 1.4 and we get 35. So what is 35 millimeters about a 50 millimeter lens will, in this case, the opening of the lands if you were to measure across the opening through the middle of the lands, not the outside end of the lens. But how much light can get through that lands? It's going to be 35 millimeters across, and so that's how they determine that this is a 50 millimeter lenses. It has the size of opening. It has this focal length. That's what the aperture is going to be, so we can figure out the size of the opening of any lands by taking the focal length dividing it by the F stop on it. So this 51.4 has a 35 millimeter opening. So Canon also makes a 1.8, Let's figure out, and it is a 28 millimeter opening, so it lets in less light. It's a little bit smaller oven opening on it. Canon makes a 1.2 lands all right, 50 invited by 1.2 is 42 millimeters. So the size of that opening is a little bit bigger, and you can has it a pretty safe guess that that bigger the opening means the bigger the glass, the bigger the lands, the more money the lands. All right, What about a few other lenses? 24 1.4 same aperture. They let in the same amount of light, but it doesn't need to have his big of opening because it's a shorter focal length lens. Let's go all the way up to a 302.8 2.82 stops less light here, but it needs to have a massive opening because it is such a long, 300 millimeter lens here, the math does not work in favor of telephoto lenses. And so this is how we get the numbers, and there is a logic and a reasoning behind it, and that's always for me. It's comforting to know that they actually mean something important. You don't have to do this math on a daily basis when you're actually pictures. Thankfully, now prime lenses, lenses that have one focal link have a variety of maximum apertures that in the Canon lineup will range from F 1.2 F 5.6. And this has a lot to do with what Focal Inc they're doing and how much you're going to spend on the particular lands. Zoom lenses will also have a variety of maximum apertures. There's a whole group of them that have a maximum aperture of F 2.8. The largest collection have this variable maximum aperture that ranges anywhere between 3.5 and 5.6. And there is another nice little collection of lenses that I think are really quite nice, good kind of middle ground between these two, with a fixed maximum aperture of F four. So let's talk a little bit about these different groups of lenses and why you would choose them. And for first off, you want to talk. About what? What is fast your heel taught photographers talk about? Do you have a fast lens? Because I need a fast lens to shoot this? Could I borrow your fast lens? What do you mean by a fast lands? Does it run really fast? You know, it means that it lets in a lot of light and allows you to shoot with the very fast shutter speed. So kind of a general definition is everything above this line is kind of fast and everything kind of below. It is kind of slow now. It's kind of interesting. Is is F to a fast lance, Um, what focal length is it? Because if it's a millimeter lands, F two is not fast. That's very normal. But if it's a 400 or 200 millimeter lands, that's a really fast lands, so it depends a lot on what focal length it iss your basic run of the mill zooms. Remember those two terrible aftermarket lenses that I started with? This is where they were. These air very slow lenses, lenses that have apertures that air in the 4 to 56 range, the fastest zooms. If you want to zoom lens and you wanted to let in as much light as possible, you're looking at Zoom's, generally in the 28 region. If you're willing to go with the prime lens, you're able tohave lenses that are much, much faster. And these air just the basic crimes. You could get into these for less than $1000. But if you're really willing to spend a lot of money on the top of the line primes, you're gonna get lenses that are very fast from wide angle out to telephoto. And so one of the things that I'm trying to show here is that if you need to let in more light what you want to get, you want to get a prime lands lens that does not zoom. Zoom complicates the lens manufacturing process, and it makes the lens much slower, which means not letting inasmuch light. So if you work in dark situations or situations, we issued a lot of people and action movement, and you need faster shutter speeds, the prime lenses probably going to be the best way to solve that problem so fast, lenses What's the big deal? Who cares about fast lenses? Well, there's a number of things going on. When you have a fast lands, you're gonna be able to set faster shutter speeds, which means you can stop action like on a basketball court in a fairly dark gymnasium or person up in a stage play that's walking back and forth on stage that doesn't have a ton of lighting. It's gonna enable you to potentially use lower I ISOS, which improve our in image quality. Of course, we can shoot under those lower light situations. It enabled us to shoot with shallower depth of field, which is gonna be very popular for you. Portrait photographers. Of course, one of the other nice things about an SLR is that you get to look through the actual lens that you are shooting, the brighter that lends the brighter the viewfinder in the easier to see your subject. It also allows for a little bit faster focusing, cause the more light that comes into your camera that's more like for the autofocus module of your camera to drive the limbs as just kind of a side benefit. Usually, these lenses have faster focusing motors in them as well. And so that kind of bonus of that feature and this is kind of another side benefits not directly with fast lenses, but in general, these air, they're higher in lenses. They tend to be better quality constructed, and they often times have a little bit more more features that they're gonna offer you in the particular lands. And so these air really some of their highest in Lindsay's. We're gonna talk more about some of the specifics in our third section, which is on features and technology. But this is kind of a quick overview of some of those things that you're getting in those fast lenses. Can I see you have a question, baby? Yeah, I do it. This is from Billy Bateman, and it had a number of votes on it. So the question was, Are faster lenses the 1.21 point four it's that are usually sharper. Then a four, for example, does sharpness come into play? Shortness is a big part of this, and we're gonna be talking about sharpness in particular in the features and Technology section, because we couldn't talk about how you design lenses and In theory, they're all sharp. I mean, they don't design blurry lenses, but they're all designed to be sharp, and the prime lenses tend to be sharper than the zooms. But this is just in a very general basis. But there's a lot of things involved, and we will be discussing that actually, in this section so way check my notes. So maximising sharpness coming up here and a little bit great. And then, with regard Teoh again the fast lenses Are they better focusing lenses, which you mentioned because they let in more light for the cameras focusing system. That is a generally true statement. For instance, that was from, and we really don't want to talk about cameras do we will talk about it for just a moment. So on some of the canon cameras, they have auto focusing modules that work with all lenses that are 56 or faster, and that is the entire lineup of canon lenses. But some of the cameras and I'm trying remember off the top my head. Five D Mark three have special sensors that work on Lee with lenses that are 2.8 and faster, and it's ah, high precision sensor. So if you put on a lens it goes to 2.8. It's enable it enables that lends to focus more precisely. And that is exactly when you need it. Because if you're focusing on my little water here with the F four lands, you got a little bit of slop room in here where you've got maybe four or five inches and focus. But when you're focusing on a 2.8 lens, you might only have one inch and focus. And with that faster lands on that particular camera. And it varies from camera to camera enables that lends to focus a little bit more precisely, and so kind of that that the critical numbers that you need to remember is 5.6 is what you need on your lens. And so if you find a lands that is an F eight lands, it's either not going to focus at all or focus very poorly. One of the lenses that's quite popular on the market right now, Sigma and Tamron are making a 1 50 to 600 that ranges. I think it's 3535 but it goes to 6.3 and I hear that I'm like, Well, wait a minute, that's beyond the 5.6 range. How is it going to auto focus? And I haven't had a chance to test that, but it will probably still auto focus, but it's it's getting weak because the general limit is 5.6. And when a lens goes to 2.8, that's the other key number. Because I know that's where you That's kind of the extra threshold for getting into that extra performance. On focusing on most of the cameras is they will have a high end F 2.8, and I have that all clearly outlined in my camera classes as I go through the focusing module in it. But that's on something like the five D mark three and even on the 70 mark to, for instance, Cool. Thank you. Okay. All right. So these lenses 35256 This is the vast majority of the basic zoom lenses on the market with cannon. And the reason that you're gonna want to buy one of these is get they have a very versatile zoom range on them. Another good reason is that they're less expensive than these faster lenses that we're gonna talk about in a moment. They're also going to be smaller and lighter. This little 10 18 is just It's a featherweight. It's super lightweight with 100 or 400. It's still a pretty big heavy lens, but it's a very versatile zoom range that would be impossible in a faster aperture at this size. Now, the types of photography I imagine doing with these types of lenses is it's pretty good general purpose stuff. And so this is where most photographers start out. You know, this 18 to 55 that's essentially basically where I got started. It was a 35 to 70 back in the day because we were using full frame film. But in this case, you know your basic simple range slow aperture, general purpose, family photography, Travel photography is going to be fine for this sort of thing because of that versatility, less expense, smaller and lighter. Those are all really good things for these types of photography. Alright, let's try the next one. F four cannons brought out a lot of F four lenses. These didn't exist years ago, and it really, really happy to see these, because compared to the 2.8 lenses which are coming next, which are, you know, kind of a favorite of the pros, these are many cases much more affordable than they in the Big Brother 2.8, their lighter, they're smaller and the zooms stay at F four. It's really nice. When you set up a camera, you set up all your manual explosions. You get everything set just the way you want and you decide. You know what? I want to zoom this from to 200 I don't want to change anything else on the camera. I don't have to go change my shutter speeds just because I zoom. And so this is great for people who are doing manual exposure photography, because you don't need to re calculate things. When you change the zoom, you can just do the exposure, and then you can concentrate on composition and getting the shot. And they have a wide variety of lenses that actually go all the way down from 11 up to 400 in the F four zooms. And so I would imagine we have a lot of people doing travel photography, a little bit of wildlife photography. That's 204 100 kind of a special lens. We'll talk more about it later. Very good for landscape photography. Landscape photographers air not shooting at 1.4 in 2.8 For most of their types of work, F four is more than enough and that lighter, smaller size is perfect for this, and these are often just a sharp, sometimes even sharper than the 2.8 zoom lenses that we're gonna get to next. So I'm a big fan of the Air Force, the 2.8, so are very popular for people who are very serious about what they're doing and usually want the cutting edge top of the line let in the most light possible. And so this is a very common number for the fastest aperture possible of any particular lens, which is gonna allow us to shoot faster. Shutter speeds have shallower depth of field for separating, are subject from the background and the zoom stay at 2.8, which is nice because it's a consistent aperture doesn't change on you. And so if somebody said I just got a job as a professional photographer doing in almost anything, and I need to buy a bunch of lenses. What should I buy? Said? Well, you should probably buy 24 72.8 and 70 to 202.8, and you'll probably be good for your first couple weeks of work until you figure out exactly what you're doing. But those are just good general purpose, very professional lenses. And so the types of photography that people are going to doing with this action. Photography, sports, dance anything where you got a lot of people or animals or things moving around a lot. Event photography. We're talking about weddings or a corporate event or gatherings or any sort of group event. We've got a lot of people moving around, maybe in dark environments, and just people tend to move a lot. And so you're going to need a faster aperture so that you can use a faster shutter speed. And if you do that a lot, that's what you're going to do here. And so a newspaper photographer news photographer is gonna probably want a 72 200. It's versatile, but it's also very fast. The F four is lighter, but that 2.8 aperture is a whole doubling of the shutter speed. And that's critical in certain types of situations and so different lenses for different types of purposes. Now there are lenses that go down to 1.22 F two. These are gonna be prime lenses. You're not gonna find zoom lenses, at least from Cannon Sigma. Just released a couple of lenses over the last couple years that are faster than 2.8. We're going to get to those when we talk about the lenses in particular. Yes, I have no problem talking about it because signals making some pretty awesome lenses thes days. But for cannons lenses right here, 1.2 to 2. We're talking about prime lenses anywhere. 50 85 200 millimeter fash shutter speeds shallow up the field. As I said, these are gonna be working under very low light conditions. So if you knew that you were always working at the university under really low light conditions and you your job was to go out and shoot regular pictures, you might need a 200 deaf, too. And that's just the only way to get your shots. And so event photography could be portrait's because portrait's like that shallow depth of field. Probably one of the more popular lenses for the Sports Illustrated swimsuit edition would be this 200 F two out on the beach. They got a big open area. They want to have their subject and really sharp focus in the background really, really blurry. That's probably, I don't know for this for a fact, but it's probably what Mawr covers of Sports Illustrated in the swimsuit edition have been shot on than any other lands, so any sort of low light action.

Class Materials

Bonus Materials with Purchase

What's in the Frame? HD
What's in the Frame? LOW
Field of View HD
Field of View LOW
Lens Keynote Parts 1-4
Lens Keynote Parts 5-8
Canon® Lens Data

Ratings and Reviews


I so appreciate what a good teacher John is. I wish I would have known this much about lenses when I first started out buying my lenses. It was hard finding information about lenses. I didn't want to spend money on a lens I wouldn't use. The better understanding we have about our gear the better photographers we will be. I have never seen a class like this. Invaluable...yes I bought the class! I am really impressed with the high quality photography classes available on Creative Live!


This was a great class not just about the lenses that Canon offers but also how each lens works. As usual, John's slides are alway informative and entertaining. There is a phrase: John has a slide for that! I am not even a Canon user and found this class to have great information for the use of each specific lens. Great work John! Thank you Creative Live for another great class!

Tami Miller

Have loved the other John Greengo classes I've watched & purchased - and this is another winner! Having been a high school/college science teacher, it is refreshing to take a course with someone who not only is extremely experienced, seems to be a computer having stored so much knowledge, but is equally concerned about making the information truly understandable to different levels. And he shares the information using every tool he can: slides, video, interactive presentations, and great quizzes. I learned so much about my Canon lenses - and lenses in general with their many components. I am excited about testing each of mine to see what macro ratio they handle, and especially appreciated the tutorial on testing each for their specific quirk that affects super sharpness. This class is great whether you own Canon lenses or not. Thanks John Greengo!

Student Work