MTF charts

[KarlKrueger]

Is there a link where you can see MTF charts for different Canon lenses? I found some references to some of the older lenses but would like to see charts for the newer ones. Canon doesn't seem to provide them on their own pages for purchasing the lenses.

[TTMartin]

---

@KarlKrueger wrote:

Is there a link where you can see MTF charts for different Canon lenses? I found some references to some of the older lenses but would like to see charts for the newer ones. Canon doesn't seem to provide them on their own pages for purchasing the lenses.

---

When Canon recently redesigned their website they disappeared.

I would like for you to have them available again too Canon!

[Danny · Accepted solution]

Hi, everyone!

We know MTF charts are essential when deciding which new lens to buy, so we still have them on our site.  Just visit http://usa.canon.com and look up any lens.  Beneath the picture of the lens, you'll find a description of its features usually followed by the text "Read more."  Click that, and you'll find the MTF charts for that lens.

Hope this helps!

[TTMartin]

---

@Danny wrote:

Hi, everyone!

We know MTF charts are essential when deciding which new lens to buy, so we still have them on our site.  Just visit http://usa.canon.com and look up any lens.  Beneath the picture of the lens, you'll find a description of its features usually followed by the text "Read more."  Click that, and you'll find the MTF charts for that lens.

Hope this helps!

---

Thanks!!!

[KarlKrueger]

Thank you Danny. Just what we needed. Except to clarify when you search for a lens the first page gives the only option below the image to "Shop Now". When selecting that link then you come to another page that gives the "read more" link.

[ebiggs1]

Warning;

You must know how to read and understand an MTF chart.  To the average person they are meaningless and could lead to wrong conclusions.

[TCampbell]

You have to be somewhat cautious when reading MTF charts and using this to compare different lenses.  The Canon charts indicate the lens performance at "wide open" using the black lines... but lenses of different focal ratios don't have the same "wide open" aperture so the comparison isn't really fair.

Canon also charts the lens performance at f/8 (in blue lines).  

But MTF charts provide limited information.  You may be as interested in the quality of a lens' blur as you are in the quality of a lens' focused areas -- but the quality of blur isn't considered.

Every so often it's possible to encounter a lens for which the MTF chart might not make you think it's a great lens... and yet when you inspect the images you realize it's actually quite a nice lens -- due to the fact that MTF charts only show one indicator of many aspects that contribute to the overall quality of the image.

Canon has an article that explains their MTF charts:  http://www.learn.usa.canon.com/resources/articles/2013/reading_MTF_charts.shtml

[KarlKrueger]

Since I'm a scientist I don't have trouble interpreting the charts having read up on how they derive these data. The plots seem relative to each other so I think comparing similar lenses gives a relative indication which lens has better performance.  It would help to know though the exact conditions they used to get each chart. Particularly at what distance are they shooting. I assume longer focal length lenses were done at longer distances but are these tests done as a specific function of the focal length? What about zoom lenses - are "Tele" and "Wide" done at the same distance?

Canon is the only one who can give these details.

[TCampbell]

But keep in mind that MTF performance is "just one thing" to consider.  

For example, if you were to compare the Canon EF 50mm f/1.4 vs. the Canon EF 50mm f/1.2 you might conclude that optically the f/1.2 version is the better lens (and it is).  But what you might not realize is that the f/1.2 version is slower to focus and a bit trickier to use and more appropriate for situations where you can take your time to get a shot.  If you're doing more candid shooting, street-photography, action photography, etc. then the f/1.4 version is probably the better choice (even though the MTF scores are lower.)

Lomography is making a reproduction of an old Petzval lens designed to mount on modern DSLR bodies. It is completely manual, uses rack focusing, and it even uses "Waterhouse stops" (it doesn't have aperture blades... instead it comes with a bunch of plates or tabs that slide into a slot on the lens, each has a hole of a different diameter.  So changing f-stops actually requires removing one tab and inserting a different tab.) Optically the quality of the lens would score poorly in meridional focus and it creates a blur effect that results in a circular shaped blur surrounding the center axis of the lens.  While this is optically "poor", the effect can be pleasing and so some people specifically want this blur -- which lenses of higher quality optics would not be able to produce. 

That's why I point out that you have to remember that the MTF curve is "just one thing" to consider among many.  A lens may be better for one purpose, but not better for another.

[ebiggs1]

"Since I'm a scientist I don't have trouble interpreting the charts ..."

Fine than you know why Tim Campbell and I say MTF charts are not the end all for telling the quality or suitability of a given lens.