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Canon Lenses: The Complete Guide

Lesson 9 of 58

Aperture Basics


Canon Lenses: The Complete Guide

Lesson 9 of 58

Aperture Basics


Lesson Info

Aperture Basics

And so the aperture is the other device in the lens. This is the second most important reason that we're choosing a particular lens. First off, we're gonna choose it for its angle of view. And generally the second reason is because of its appetite. There's a few cases where we choose lenses because we need that specific aperture first. But in general, it's the second reason that we choose the lens. And in this section, we're gonna talk a little bit about aptitude range. Not very long, because this is kind of more photo. Wanna one stuff. We're going to spend quite a bit of time going through some of the more advanced in esoteric topics when it comes to aperture. So first off, just cover our basis with all of our new photographers. We don't want to be mean and jumped past them. I want to bring them along with us, talk quickly about the aperture range in a particular lands, and so each lands is gonna have an aperture that you can close down and set two different apertures. So a lens it go...

es to 1.4 is gonna have a very shallow depth of field in this illustration. Here, you can see those red hash marks over on the right hand side are illustrating the front edge of focus and the back edge of focus. So that is our depth of field between those two lines. As we stop our aperture down each time we get a little bit more depth of field with each subsequent setting, and this is the aperture unit you can see closing down in the middle of the lens, letting in a little bit less light that we're gonna need to compensate with on shutter speeds. So when we get down all the way to 22 in this particular example, that's as much depth of field as we can get. And you can see on the right hand side of the screen that we've got everything from 22 to the 33 mark in focus, but not stuff beyond it. So it extends greatly, but it does have limitations, and so that's the range. Different lenses are gonna have different numbers that maybe extend further in either direction. And so the visual that I keep in my mind and this is one of the most difficult things for newcomer photographers is 1.4 is a very small number, but it's a very big opening, and 22 is a big number. But it's a very small opening. In a case like this. Let's say we're at F 2.8 and we move to 2.0, we are opening up our appetite. It's kind of terminology we like to use, and in that case it's a full stop of light, which means it's double the amount of light when we go from 28 to 2 point. Oh, if we were to go the other direction from to Wait F four, which is the nest next number in the Siri's going from F four were stopping our aperture down, and we're letting in half assed much light. F four is the next number on our Siri's, and that is also a full stop, so a full stop can be more or less. You need more information as to which direction you're going, and so that's one of the things that we're doing in our cameras. There's more of this information in my fundamentals class. We're gonna pass by this pretty quickly because this is a slightly more advanced class. Now. Canon has three different lenses. We had somebody asking about these three different lenses. They make a 8 51 4 in a 51 to question for all of you here in the studio and at home. If each of these lenses is set to 2.8, will they have the same exposure and the same depth of field? Now? What's different is that we have a 1.2 lens, a 1.4 lens in a 1.8. But if they're set at 2.8, are they really setting it? Are they really letting in the same amount of light for the exposure and for the depth of field? And so I don't know how to address this question, but think about it. What is your answer? Yes or no? Let's just do an audience participation poll. Let me just raise your hand. If you think the answer is yes, it's the same and raise your hand. If you think it's no, they're different. Okay? The answer is they're the same, all right. And so one of the things that I was confused about was if I bought a faster lens. And this is a faster lands. No matter where I said it, it's always faster than everything else. Nope, You got to shoot it at 1.2. If you want to be faster when you have these three photographers using these three different lenses and they're set a 2.82 point eight is gonna be the same exposure in the same depth of field. Now, having said that, these are three very different lenses the size of the focusing ring, the construction, the bouquet, the out of focus area. All sorts of things were different. But if you're gonna be buying the faster lens, you're often buying it for the fact that it can shoot down at this 1.2 appetite.

Class Description

Working with interchangeable lenses can be both exciting and daunting to all levels of photographers. Canon® Lenses: The Complete Guide with John Greengo will prepare you to select the right lens and get the most out of all of your lens investments.

John Greengo is the master of making complex photography concepts easy to understand and in this class, he’ll bring all of your Canon EOS DSLR lens options and operations into focus. 

You’ll learn about: 

  • Focal length and aperture
  • Canon zoom lenses
  • Which lens accessories to buy
  • Third-party lenses
  • Maintaining a lens system

John will cover the full range of Canon lenses, from ultra-wide to super-telephoto, zooms to primes, fisheye to perspective control. You’ll learn how to match the right lens to your needs and get insights on the best ways to use it.

Whether you are thinking about buying a new lens or just want to get the most out of what you already have, Canon Lenses: The Complete Guide with John Greengo will help you out.


  1. Class Introduction
  2. Canon Lens Basics

    John Greengo gets you up-to-speed on the basics of working with interchangeable Canon® lenses.

  3. Focal Length: Angle of View
  4. Focal Length: Normal Lenses
  5. Focal Length: Wide Angle Lenses
  6. Focal Length: Telephoto Lens
  7. Focal Length Rule of Thumb
  8. Field of View
  9. Aperture Basics
  10. Aperture: Maximum Aperture
  11. Aperture: Equivalent Focal Length
  12. Aperture: Depth of Field
  13. Aperture: Maximum Sharpness
  14. Aperture: Starburst Effect
  15. Aperture: Flare
  16. Aperture: Hyperfocal Distance
  17. Camera Mount System
  18. Canon Lens Compatibility
  19. Canon Lens Design
  20. Canon Lens Composition
  21. Canon Lens Shape
  22. Canon Lens Coating
  23. Canon Lens Focusing
  24. Lens Autofocus
  25. Canon Lens Image Stabilization
  26. Canon L Lenses
  27. Image Quality
  28. Canon Zoom Lenses: Standard
  29. Canon Super Zooms
  30. Canon Wide Zooms
  31. Canon Telephoto Zooms
  32. Prime Lens: Normal Lenses
  33. Prime Lens: Moderate Wide
  34. Prime Lens: Wide Angle
  35. Prime Lens: Ultra-Wide
  36. Prime Lens: Short Telephoto
  37. Prime Lens: Medium Telephoto
  38. Prime Lens: Super Telephoto
  39. 3rd Party Lenses Overview
  40. 3rd Party Prime Lenses
  41. 3rd Party Zoom Lenses
  42. Lens Accessories: Filters
  43. Lens Accessories: Lens Hoods
  44. Lens Accessories: Tripod Mount
  45. Lens Accessories: Extension Tubes
  46. Lens Accessories: Extenders
  47. Macro Lens: Reproduction Ratio
  48. Macro Lens: Technique and Choices
  49. Fisheye: Technique and Choices
  50. Tilt Shift: Techniques and Choices
  51. Make a Lens System Choice
  52. Choosing A Portrait Lens
  53. Choosing A Sports Lens
  54. Choosing A Landscape Lens
  55. Best Lenses for You
  56. Lens Maintenance
  57. Buying and Selling Lens
  58. What is John Greengo's Favorite Lens?



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!

a Creativelive Student

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!


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!