Question for 85/1.2 owners re CA

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Archive 2009 · Question for 85/1.2 owners re CA

slobodan
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p.1 #1 · Question for 85/1.2 owners re CA

I shot this with my 85/1.8 @ f/2, natural light:

What bothers me is a quite visible green and purple chromatic aberration (me think):

Upper left corner at 100% (note the "green" hair):

And lower right corner:

The question for 85/1.2 owners: is such CA equally visible with your "L" lens?

Aug 28, 2009 at 02:26 AM

PetKal
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p.1 #2 · Question for 85/1.2 owners re CA

Yes, and more......all the way up to f/2.2 my 85L MkI is quite susceptible to purple/green fringing.
BTW, very nice portrait of a very pretty girl.

Aug 28, 2009 at 02:52 AM

MTBtrials
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p.1 #3 · Question for 85/1.2 owners re CA

Wow... I wouldn't notice anything like that.

I rented the 85L to shoot a wedding and quickly realized that you have to shoot without any comp (especially if you open it up a little bit) or else you get bad CA when shooting anything too contrasty.

(on a 40D mainly wide open at 1.2)

Aug 28, 2009 at 02:54 AM

Greg Feldman
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p.1 #4 · Question for 85/1.2 owners re CA

Yes. Superfast lenses are like that.

Aug 28, 2009 at 03:00 AM

slobodan
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p.1 #5 · Question for 85/1.2 owners re CA

PetKal wrote:
Yes, and more......all the way up to f/2.2 my 85L MkI is quite susceptible to purple/green fringing.
BTW, very nice portrait of a very pretty girl.

Thanks... she is ten years old. What bothers me even more is that none of the CA sliders in Lightroom has any effect whatsoever on that fringing... with all other lenses, it is usually a breeze to get rid of CA in Lightroom.

Aug 28, 2009 at 03:07 AM

Dawei Ye
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p.1 #6 · Question for 85/1.2 owners re CA

Yeah those sliders don't work, they are more effective at cleaning up lateral CA than longitudinal CA

Aug 28, 2009 at 04:25 AM

Lance Couture
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p.1 #7 · Question for 85/1.2 owners re CA

slobodan wrote:
PetKal wrote:
Yes, and more......all the way up to f/2.2 my 85L MkI is quite susceptible to purple/green fringing.
BTW, very nice portrait of a very pretty girl.

Thanks... she is ten years old. What bothers me even more is that none of the CA sliders in Lightroom has any effect whatsoever on that fringing... with all other lenses, it is usually a breeze to get rid of CA in Lightroom.

If you head over to the Post Processing Forum, there are lots of really great techniques people can show you to clean up CA's like that in PS.

Aug 28, 2009 at 05:50 AM

Daan B
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p.1 #8 · Question for 85/1.2 owners re CA

Try it @ f/1.2... if you think this is a bad case of CA

Aug 28, 2009 at 07:47 AM

Daan B
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p.1 #9 · Question for 85/1.2 owners re CA

Dawei Ye wrote:
Yeah those sliders don't work, they are more effective at cleaning up lateral CA than longitudinal CA

The only LR tool that has some effect on the fringes is the "defringe" checkbox.

Aug 28, 2009 at 07:48 AM

skibum5
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p.1 #10 · Question for 85/1.2 owners re CA

slobodan wrote:
PetKal wrote:
Yes, and more......all the way up to f/2.2 my 85L MkI is quite susceptible to purple/green fringing.
BTW, very nice portrait of a very pretty girl.

Thanks... she is ten years old. What bothers me even more is that none of the CA sliders in Lightroom has any effect whatsoever on that fringing... with all other lenses, it is usually a breeze to get rid of CA in Lightroom.

yeah front/back CA is harder to correct

most fast canon lenses are not full APO designs so they only shift up blue to red and leave green behind so you get magenta in front of focus and green behind it

the canon super-tele are fully correct, as appear to be the macro lenses

it varies in degree lens to lens the 50 1.4, 85 1.8, 85 1.2, 135 2 certainly have it noticeably

Aug 28, 2009 at 07:55 AM

Uncle Mike
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p.1 #11 · Question for 85/1.2 owners re CA

slobodan wrote:
What bothers me even more is that none of the CA sliders in Lightroom has any effect whatsoever on that fringing... with all other lenses, it is usually a breeze to get rid of CA in Lightroom.

Those sliders only fix lateral CA.

You're seeing what I think is correctly called spherochromatism. Longitudinal CA is corrected in the focal plane, but outside the focal plane it's not. It seems to be a result of a complicated lens trying to correct a lot of stuff while ignoring this issue. I don't believe that the cheapie Canon EF 50mm f/1.8 has this issue.

For the price of an "L" lens, one is entitled to expect more perfection, in my worthless opinion.

Aug 28, 2009 at 02:37 PM

slobodan
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p.1 #12 · Question for 85/1.2 owners re CA

MTBtrials wrote:
... I rented the 85L to shoot a wedding and quickly realized that you have to shoot without any comp...

I am not sure I understand what you meant by "shoot without any comp"?

Aug 28, 2009 at 03:58 PM

slobodan
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p.1 #13 · Question for 85/1.2 owners re CA

Daan B wrote:
Try it @ f/1.2... if you think this is a bad case of CA

Just to make sure there is no misunderstanding, the original shot was done with a 40D and 85/1.8 lens (i.e., not the "L" one). The reason I titled this thread as a question for 85/1.2 owners is to basically ask if shelling out $1500 more for the "L" lens would eliminate or reduce the problem with CA... based on the replies so far, it seems it would not, unfortunately. Furthermore, given that the above shot is done with a crop sensor, it seems logical that on a full frame the CA would be even more pronounced.

Aug 28, 2009 at 04:06 PM

slobodan
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p.1 #14 · Question for 85/1.2 owners re CA

Daan B wrote:
... The only LR tool that has some effect on the fringes is the "defringe" checkbox.

Tried that as well, no visible effect.

Aug 28, 2009 at 04:08 PM

Uncle Mike
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p.1 #15 · Question for 85/1.2 owners re CA

slobodan wrote:
Furthermore, given that the above shot is done with a crop sensor, it seems logical that on a full frame the CA would be even more pronounced.

No, just the opposite seems logical. A green fringe with a width of 20 microns would cover a greater percentage of the picture area on an APS-C camera than on a FF camera.

Aug 28, 2009 at 07:26 PM

Ernie Aubert
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p.1 #16 · Question for 85/1.2 owners re CA

I once saw on a web site a set of images of a mannequin head shot with the 85 1.8, the 85 1.2L I, and the 85 1.2L II, and the CA diminished progressively with price. I would expect that you'd have had less of it with the 1.2 II at the same aperture. (That would qualify as my worthless opinion.)

Aug 29, 2009 at 12:28 AM

phuang3
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p.1 #17 · Question for 85/1.2 owners re CA

My suggestion is to use a long tele for this kind of portrait. Try a EF135/2 or EF200/2 which has much better LCA correction.

Aug 29, 2009 at 01:29 AM

rscheffler
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p.1 #18 · Question for 85/1.2 owners re CA

Ernie Aubert wrote:
I once saw on a web site a set of images of a mannequin head shot with the 85 1.8, the 85 1.2L I, and the 85 1.2L II, and the CA diminished progressively with price. I would expect that you'd have had less of it with the 1.2 II at the same aperture. (That would qualify as my worthless opinion.)

Are you thinking of this? http://www.wlcastleman.com/equip/reviews/85mm/index.htm

BTW, he writes in the above review comparing the 85 1.8, 85L and 85L II: Birefringence patterns produced from f/1.4 to f/4 with the 3 lenses on an EOS-1Ds Mark II are shown here. No differences among the lenses were detected in birefringence induced in metallic/reflective objects at wide apertures with the three lenses using the 1Ds Mark II or an EOS 20D (20D images not shown)

Aug 29, 2009 at 05:25 AM

Ernie Aubert
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p.1 #19 · Question for 85/1.2 owners re CA

That was it.

Aug 29, 2009 at 06:34 PM

sboerup
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p.1 #20 · Question for 85/1.2 owners re CA

Not to be insulting, I'm just surprised people worry about this much CA in their pics. I mean, its hardly noticeable at 100%, something you wont see in a print. // end rant

Aug 29, 2009 at 09:25 PM

skibum5
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p.1 #21 · Question for 85/1.2 owners re CA

phuang3 wrote:
My suggestion is to use a long tele for this kind of portrait. Try a EF135/2 or EF200/2 which has much better LCA correction.

the 135 f/2 has quite a bit

the 200 f/2 should be fully corrected against it though, all the other lenses of that type from canon are

Aug 29, 2009 at 09:48 PM

slobodan
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p.1 #22 · Question for 85/1.2 owners re CA

sboerup wrote:
Not to be insulting, I'm just surprised people worry about this much CA in their pics. I mean, its hardly noticeable at 100%, something you wont see in a print. // end rant

No offense taken... however, CA is very, very visible (at least to a trained,e.g., photographer's eye) at anything above 4x6. Just pay attention to it in magazines and you will notice it already in single-page images (where photographers did not bother to remove it, of course). Also, there are instances where images are printed equivalent to 100% screen viewing (e.g., bridal portraits)... in the example of my image above, it would take a 24"x30" print to see the detail as if viewed on screen at 100%. These days more and more clients require original files on a disk (or full-size files online), and they view them on their computer screens... and you can not really count on them not being tech-savy enough to find the 100% view button.

Aug 29, 2009 at 09:56 PM

phuang3
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p.1 #23 · Question for 85/1.2 owners re CA

I think LCA is fine in most situation. There is only one situation I hate to see LCA - the jewelry photography. If you shoot platinum rings, LCA is very very distracting. Normally, I'd stop down to prevent this problem. Other than that, most clients won't notice the existence of LCA.

Aug 30, 2009 at 01:53 AM


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