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Canon Lens Shape

Lesson 21 from: Canon Lenses: The Complete Guide

John Greengo

Canon Lens Shape

Lesson 21 from: Canon Lenses: The Complete Guide

John Greengo

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Lesson Info

21. Canon Lens Shape

Lessons

Class Trailer
1

Class Introduction

07:11
2

Canon Lens Basics

14:12
3

Focal Length: Angle of View

11:31
4

Focal Length: Normal Lenses

09:43
5

Focal Length: Wide Angle Lenses

18:15
6

Focal Length: Telephoto Lens

21:27
7

Focal Length Rule of Thumb

15:36
8

Field of View

10:14
9

Aperture Basics

04:41
10

Aperture: Maximum Aperture

18:44
11

Aperture: Equivalent Focal Length

07:48
12

Aperture: Depth of Field

06:23
13

Aperture: Maximum Sharpness

08:33
14

Aperture: Starburst Effect

05:18
15

Aperture: Flare

06:48
16

Aperture: Hyperfocal Distance

19:32
17

Camera Mount System

14:57
18

Canon Lens Compatibility

14:26
19

Canon Lens Design

12:29
20

Canon Lens Composition

04:30
21

Canon Lens Shape

05:50
22

Canon Lens Coating

06:53
23

Canon Lens Focusing

14:10
24

Lens Autofocus

08:17
25

Canon Lens Image Stabilization

06:57
26

Canon L Lenses

10:18
27

Image Quality

09:46
28

Canon Zoom Lenses: Standard

17:50
29

Canon Super Zooms

05:20
30

Canon Wide Zooms

09:48
31

Canon Telephoto Zooms

16:09
32

Prime Lens: Normal Lenses

09:19
33

Prime Lens: Moderate Wide

07:01
34

Prime Lens: Wide Angle

05:33
35

Prime Lens: Ultra-Wide

09:23
36

Prime Lens: Short Telephoto

09:03
37

Prime Lens: Medium Telephoto

08:59
38

Prime Lens: Super Telephoto

13:59
39

3rd Party Lenses Overview

06:01
40

3rd Party Prime Lenses

15:25
41

3rd Party Zoom Lenses

26:28
42

Lens Accessories: Filters

33:42
43

Lens Accessories: Lens Hoods

09:58
44

Lens Accessories: Tripod Mount

04:51
45

Lens Accessories: Extension Tubes

04:30
46

Lens Accessories: Extenders

13:11
47

Macro Lens: Reproduction Ratio

18:59
48

Macro Lens: Technique and Choices

25:59
49

Fisheye: Technique and Choices

18:49
50

Tilt Shift: Techniques and Choices

27:08
51

Make a Lens System Choice

05:37
52

Choosing A Portrait Lens

17:21
53

Choosing A Sports Lens

17:31
54

Choosing A Landscape Lens

10:39
55

Best Lenses for You

08:46
56

Lens Maintenance

11:19
57

Buying and Selling Lens

11:15
58

What is John Greengo's Favorite Lens?

08:37

Lesson Info

Canon Lens Shape

So we got our glass compounds. We've got the glass that we got the type of glass we're gonna do now. Once we have this, we need to shape it all right. Now, most lenses are gonna be shaped into a spherical, rounded type element and that works out well for most lenses. We can you do that most of the time and it's gonna come out fine, but from time to time, depending on the chemical compound, depending on the way the light travels through. Here are red, blue and green points of light. Don't end up in the right area. How do we fix this? Well, one of the solutions is to create an ass spherical element that has a non perfectly smooth exterior. It's it is smooth, but it's not a rounded in the way that a spherical forms of sphere alright. And by doing that, if they do it just right, they can fix this problem. So this could potentially reduce spherical aberrations astigmatism, and it can also reduce the number of elements, which means we can make a smaller lands. You'll find these in white angl...

es, lardo, large aperture lenses and compact zooms where they're really trying to reduce the size of the lens quite a bit. And so there's a long list of lenses that are using this aspirate kal glass. And as I say, I'm not involved in the process of making. But I would think polishing a spherical element is a whole lot easier than an astrological one, because the types of machines they have will take, like, 40 lenses in them and just be kind of rubbing them all around, smoothing them all up when it comes to ask Miracle. It's a whole different system that they had to develop in order to work with these types of glass elements. And so there are different types of s mericle elements, ground and polished. That sounds pretty good to me. Molded glass not quite as good, so they just kind of form it in that shape rather than grinding it down. And then there are precision moulded plastics that they will use, and that's more likely to be found in some of their point and shoot and smaller in cameras. And so they are technically plastic lenses in there, which some people are very concerned is that a glass lens or plastic lens. Well, you know what that they could do with plastics. They could make him as good or better than standard glass. D o stands for diffraction optics, and it's only used in a couple very unique, very special lenses from Canon. So one idea says, we're all designing our lenses right is Excuse me. What if we just made everything smaller when it that I mean OK, here's our big lands. Let's just make the lens and all the lens elements smaller. What's the problem with that? Can't we just reduce everything? Well, if we do that, it's quite possible that are light rays once again, do not end up at the same point and we're not getting sharp focus. So nice idea. Just reduce everything, make everything half the size and it will work doesn't always work that way. So another solution that they found was a diffraction of scratch structure, and they found that this was fairly good, and they could use this to focus the light in on the sensor and get a pretty good image out of it. But it wasn't perfect. Perfect. Some of the light dispersed off to the side. How do we fix this out and what they're currently using is they're using a dual layered, multilayered refractive structure that corrects for these problems. Redirects light properly in, and they're able to reduce the size of the lens significantly in some cases in order to get a nice, sharp image. So they designed a 400 millimeter F four lens, and they said, You know what? This thing is going to be 31.7 millimeters in length. They know this stuff ahead of time, exactly what they're going to need. But we want to design something that is significantly smaller with these new optics. And this is how they came up with their 400 d o. D fractal optic lens. They just introduced their second version of this. And if you compare what a normal 400 is versus the D O, it is a big savings in size and in wait. So 27% smaller, 31% lighter in size. Very nice thing to have. You will also find this in another lens that they have. They have a standard 72 300 lands pretty typical. It's 14 centimeters, almost six inches in height. They do have a triple layer Dio design in their 300 d Oh, let's 30% smaller, 18% lighter. This is all well and good, but life is not perfect in the world of D. L. Because of the way the lenses air cut, he will sometimes get flare issues that don't look like flare from a normal lens. And they can't just implement this on every single lens. It just doesn't work out, which is why we don't see it on everything out there. There's only this compact zoom. There is the old 400 the new 400 which, by the way, is much sharper than the old one that has this dio technology. They kind of let it lie dormant for about 10 years, and I kind of wondered if they were going to do anything more with it. Because, optically speaking, the 400 the 72 300 are among the weaker canon lenses when it comes to sharpness and overall image quality. And so it's not a perfected technology, but I will have to say that the 400 F four and all the image tests that I've seen is pretty darn phenomenal. It looks really, really good. And so maybe they have kind of figured out any of the little bugs in there because it's looking really good these days on that latest lens, at least so that's a special lens designed for those lances.

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

user-b3a96c
 

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!

Abbeylynne
 

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!

Student Work

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