My T1i + Canon 50 1.4 - TONS of axial CAs @ f/2

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Notice all the bokeh and axial CA in the above photo. This was shot with my Rebel T1i and Canon 50mm f/1.4 USM. I was looking at Bryan

That does seem like quite a bit, however this particular situation may be a tough one (the sun is shining on the CA shoulder, right? There is no CA on the other shoulder). I don

It seems on shots where I was more backlit there was more CA. Which would make sense due to the high contrast border between the player and background, but I guess I was just shocked because I thought lenses never performed worse than on the ISO 12233 charts

<span style="color: #000000;"]<span style="background-color: #ffffff;"]The ISO 12233 chart light conditions and your scene light conditions are completely different. You can't even compere them.

And if in ISO 12233 chart test CA were only between F/1.4 - F/1.8, doesn't mean that in various conditions you won't see CA with narrower aperture. In certain conditions you can see CA even with F/4 or F/8.

If there would be special lens tests of CA characteristics and there will be written, that canon 50 mm F/1.4 shows CAs only between F/1.4 - F/1.8 and you would get visible CA for example with F/4, then we could consider, that there is maybe bad copy or something else.

ISO 12233 chats tests is mainly for sharpness [:)]

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Originally Posted by mmodica

Notice all the bokeh and axial CA in the above photo. This was shot with my Rebel T1i and Canon 50mm f/1.4 USM. I was looking at Bryan's ISO crops of the fifty and on his CA was really only present between f/1.4 and f/1.8. How come I'm seeing so much of this stuff at f/2?

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All fast primes exhibit some degree of axial CA, and it's always worst at high-contrast transitions like the one on the subject's right shoulder, and at the contrast transitions in OOF specular highlights (which is why axial CA is also referred to as bokeh fringing). It does improve with stopping down, but only slowly.


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Originally Posted by mmodica

<span>I wish I was shooting L...<span>

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It wouldn't help much, in this case. When I tested axial CA of the 85mm f/1.2L II, I found that it was evident at f/2.8, and even somewhat evident at f/4.

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Originally Posted by mmodica

I wish I was shooting L...

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<span style="color: #000000;"]Look at the tests in the photozone.de


<span style="color: #000000;"]Canon 50 mm F/1.2L


<span style="color: #000000;"]http://www.photozone.de/images/8Revi..._12/fringe.jpg


<span style="color: #000000;"]Canon 50 mm F/1.4


<span style="color: #000000;"]Comparing Chromatic Aberrations (CAs) section of both lenses, seems clearly evident, that 50 mm F/1.4 could show less CAs than <span style="color: #000000;"]"<span style="color: #ff0000;"]L" version.



<span style="color: #000000;"]The "<span style="color: #ff0000;"]L" doesn't mean, that lens always will have better CA characteristics.



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Interesting, thanks for the info guys.


I

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Originally Posted by mmodica

I'm wondering though, what is it about primes that causes the axial CAs? Is it just the ultra-large aperture?

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Yes :)


I don't know anything about lens design, but I'm pretty sure it isn't harder to make a prime than a zoom. I'd be very surprised if nice primes (like the 50 f/1.4) show more CA than zooms if you compared at similar f numbers.

Hmm. Interesting. I