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Image Quality

Lesson 27 from: Canon Lenses: The Complete Guide

John Greengo

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Lesson Info

27. Image Quality


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

Image Quality

one of the ways that you can judge the image quality can actually post this. On their website is the M T F charts, which judge the sharpness of your images. And so this is what Nmpf chart looks like. And what it's doing is it's ranking the sharpness from the center to the edge of the frame, in different types of areas of contrast. And so, at zero line that is the center of the frame. As we go out to 5 10 15 that is the edge of the frame, and you'll notice that these and I guess I'll give you the other statistic. Everything above 0.6 is considered sharp. Everything above 0.8 is considered very sharp on the lens on the left, the center of the image is super sharp, and it gets a little bit weaker as it gets out to the edge of the frame. This second example shows the this lens is pretty sharp in the middle, but once you get away from the middle, it loses a lot of sharpness, and it's gonna be soft in the corners, and so this is less than desirable. What you ideally want is a line straight ...

along the top, and you can find these empty F charts for all the different lenses out there. A little side note just got a funny little thing. Um, thes air, all theoretical. And they're not actual. So this is all with the lens Designers theoretically think is happening in your lands, and there are different ways of testing them. And what they publish is theoretical ones, not the actual ones. But there are places that you can look up online if somebody has done a test to see exactly what they look like, Dxl Mark is an interesting place. I think they're out of France, and they measure cameras and lenses for quality in many different ways. And one of the ways that they could do it is by doing kind of, ah, collection of a lot of features. So they're not just judging a lens on sharpness. They're looking at how much distortion vignette ing transmission, chromatic aberration, and they're doing a balance of where which lenses overall, the better lens. And they kind of have different weightings on these as to how good the lenses are, and I decided to go in, look up the canon lenses and pull off the list off the 10 worst lenses that Cannon makes according to their standards here. And so here's our list of 10 lenses thes air their bottom 10 lenses and you'll see a lot of zooms. A lot of slow actress slow Apertura zoom lenses on here. And you do have to question their ranking system and their methodology because it's in perfect because there are lenses on that list that I would have no problem recommending Using There are lenses that I would have no problem using and getting great images often but their ranking fairly low in this particular case. Now let's take a look at their top 10 lenses, and what you'll notice is a large number of L lenses. But interestingly, the top two are not. Ellen's is. In fact, the number two position lens is a 20 plus year old lands very old technology, sharpness wise. It's not one of the 10 sharpest, but all these other features are quite good, so it actually ends up very high in the ranking system. And so depending on how you play with these numbers, this is a very subjective number here but yes, all of these air Fantastic. Really nice lenses. Interesting Number 10 On the last $ lands, you can get one of their top 10 lenses for 100 and 50 bucks. Fact there a couple of these lenses are, well, well under $1000. And because I don't work for Canon and I don't care about promoting or not promoting Cannon, let's take a look at the 10 best non canon lenses and what you're going to see here is a lot of lenses from Zeiss. We'll talk about sites in the next section. Sigma has been doing really well with their lenses, and so they've got some in there and holy smokes. Number nine. Sam Yang. How did they get in there? They're they're kind of They're kind of new kid on the block or in this type of arena, But they made a lens. It's really sharp. It ranks up there. It's not that much money. And so those are some of the top 10 and bottom 10. Not really a big deal, but the diaphragm, the aperture in your lands is controlled electronically. It's powered electronically, and amazingly, they've had no real improvements or changes since the day it came out. It's a fully electronic transmission, and there's really been nothing. It's worked perfectly since Day one, and so it's better than the mechanical systems that some other companies air still using. And it's in all the F lenses, and there's really no differences in it. But that's just part of what's going in the lands. Internal reflections We talked a little bit about this before. It causes flare ghosting. It's when light is bouncing around. And so the design of the lens and the construction of the lands have a big part in tow. How much light is bouncing around? Cause we want light that goes straight through to the image sensor, so they put all these reflective coatings on the edges of it. In fact, if you've looked in some of the back of some lenses, it's kind of like the soft black felt in material. And it's that filter material because that just absorbs the light and it doesn't reflect off of it. And that's what the flocking is. Even the design of the aperture can reduce the amount of flare and ghosting they actually sometimes have little blocks and grooves and little areas where it just blocks. A little bit of like that would normally come in and cause a problem in there and some of these air actually moving back and forth. There's no lens element. It's just trying to block some of the light that's moving from it. Just a little side note here. A zoom lens is a lens that can change Focal Inc and maintain focus. Most people I would, I don't even know, because it's not clearly stated. But we have a whole bunch of zoom lenses what we call zoom lenses, but they're not really zoom lenses. What they are, in actuality are very focal lenses and a very focal lens that changes focus as you change the focal ing. If you've ever focused on something and zoomed in on it and it's no longer in focus, that is a very focal let's. It's much easier to make a very focal lens than it is. Resume winds. It would be preferable to have a zoom lens where it holds the focus, but this is why we no longer use the technique of zooming into focus and then pull back and taking the picture because your camera or your lens may change Focus. And so you should focus at the focal length that you plan to take the picture out. Some of the lenses suffer from creep, not creeps. Creep. Creep is where you're carrying a land and sea verse. One of these lenses reverse to here. So the 104 if you're carrying it like this, if certain positions it could get kind of loose. It kind of creeps out on you like this. And as you're carrying lands, it kind of gets a little long. It's like no to keep it up here. And so a number of lenses will have a lock on it so that it doesn't. There it is. It's creeping on me. The weight of the lands is carrying it out. And so there's a number of lenses that have a lock on it, and it's just simply for when you're walking around and you don't want the lens extending out, banging around on stuff. The cannon E f mount is 54 millimeters across. The Nikon lens is 44. Let's do a little math. 54 44. It means cannon is bigger than Nikon. What about that flans distance? The flans distance is 44 in Canon and 46.5. You know what this means? This means is that we can make an adapter. Noble flex makes one and weaken mounted on our camera body and we could mount a Nikon lens on our camera body. The last thing is, they have been making improvements along line, and so there's a bunch of 72 to hundreds. This is an old one. It doesn't have image stabilization. And so this is known as the non I S model. The next one has image stabilization on it. It says I asked, We call it version one because now there is a version two out that actually is labeled as version two. And so, as they make improvements, you'll see lenses get replaced into these second versions. So if you want to find out how old your lenses, there is a date code on your lens. Now, from 1960 to 2008 they were using this six letter to letter for number code, and I'm gonna give you the key code here. And this is where the pdf will come in handy is the first letter refers to the factory where it was made. The next one is the year you in this case, if we look on the list, was either 1980 or 2006. We consume eyes. It was because it's an autofocus lands. 08 is the month. That's pretty easy to figure out, And if you can figure out what the last one is you can give me a ring and I'll put it in my next class. And so that's how you figure out how old it is. But currently they're using a 10 digit system where the 1st 2 digits are a date code of the year and month that it was made. According to this chart that you see on screen now and 27 if we follow the list is March of 2015 and they're just adding a new date each month to the numbering system. Assuming that this goes forward, you can kind of follow it and figure out what it is in the future. But if you want to figure out the date that your lenses manufactured, this should get you very close to that date

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!

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!


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