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07/06/2008 05:54:46 PM · #1 |
Hi there - can any of you Canon EF 85mm f/1.2 II lens owners tell me if this amount of chromatic aberration is normal on this lens? I'm using it with the 40D. f/4.0 and above seem to be ok, but f/3.2 and below starts to showing CA, with f/1.8 and below show a LOT of CA. Very disappointing if this is "normal" for this lens. Should I be calling Canon for a new lens, or is this to be expected.
Thanks in advance for you help!
  
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07/06/2008 06:04:37 PM · #2 |
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07/06/2008 06:08:02 PM · #3 |
| try manually focus, if you just can't get ride of it then send to canon... otherwise I'd say this is normal for a 85mm under f/4 |
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07/06/2008 06:22:22 PM · #4 |
What you are seeing is a combination of CA and purple fringing. The fringing is common to all very wide aperture lenses when extremely bright specular highlights show up in shots. You *do* have some actual CA showing up, but it is on edges that are just outside the plane of focus. All colors may be meeting as desired at the plane of focus, but diverge behind (or in front of) it. Your example (blown highlight transition to black) is pretty much the worst possible test for this. OK, well, except possibly for astro work.
Bottom line, I'll bet there is nothing wrong with your lens. |
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07/06/2008 06:57:24 PM · #5 |
You should expect the image to get soft as you get to wider and wider apertures. Here's a website that lets you see a comparison between lenses, or even the same lens at different apertures: Canon 85mm 1.2L /f1.2 versus f/4
The above link starts out showing you what you'd see at f/1.2 and as you hover your mouse over it, it changes to what you'd see at f/4. Personally, I think it's a bit exaggerated as I've shot that lens at f/1.2 and have been *very* pleased with the results (even understanding that they get a bit soft). But the other issue is your specular highlights which Kirbic has already discussed, so I'll leave it at that.
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07/06/2008 07:44:58 PM · #6 |
| Oh, FWIW, the magenta fringing on highlights can normally be completely eliminated in post, but completely desaturating just the pure magenta color, since it normally appears nowhere else, and even where it does, you can usually mask magentas you wish to retain. |
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07/06/2008 08:09:48 PM · #7 |
Thanks for the input! Not sure I am happy with the answers though. :-( Pretty expensive lens to produce such issue. I read this was the quintessential wedding lens for Canon - how do you wedding photog's get around this issue? (other than to not shoot below f/4)
Message edited by author 2008-07-06 20:10:35.
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07/06/2008 08:31:50 PM · #8 |
Originally posted by macpapas:
Thanks for the input! Not sure I am happy with the answers though. :-( Pretty expensive lens to produce such issue. I read this was the quintessential wedding lens for Canon - how do you wedding photog's get around this issue? (other than to not shoot below f/4) |
It's not really the lens, at least with the magenta franging... it's a function of the digital sensor. Large aperture lenses shot wide open have the unique characteristic that light hits the sensor from angles that are way off vertical. When combined with very bright highlights, this will produce some magenta fringing.
The slight CA is a function purely of a very high contrast edge slightly out of focus, and this *is* a function of the lens, however it is almost never a concern in practice, and if desired is correctable in post. |
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07/06/2008 11:09:42 PM · #9 |
Most of the time you're not dealing with such hard specular lights... but think about it this way: At f/1.2 you can "get the shot" in many situations where even an f/2.8 lens cannot. So as a wedding photographer, you have to ask yourself, would you rather get the shot or not? :-)
Open it up when you need it wide open. Stop it down when you don't. All lens are at the sharpest a couple of stops from wide open ... this one's no different. The good thing is, it gets sweet at an aperture where some lenses are just starting.
I love that lens. The only thing I don't like is the slow focusing mechanism. Wish Canon would fix that. Otherwise, it's a perfect lens.
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07/07/2008 04:03:05 PM · #10 |
Originally posted by macpapas:
Thanks for the input! Not sure I am happy with the answers though. :-( Pretty expensive lens to produce such issue. I read this was the quintessential wedding lens for Canon - how do you wedding photog's get around this issue? (other than to not shoot below f/4) |
The issue is that this lens is perfectly sharp by 2.2 and exceptional by 2.8 where a fast lens such as a f/2.8 just isn't. It's more about getting the shot which is paramount for wedding photography. |
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07/07/2008 05:22:26 PM · #11 |
Originally posted by macpapas:
I read this was the quintessential wedding lens for Canon - how do you wedding photog's get around this issue? (other than to not shoot below f/4) |
Buy the 1.8 version :)
Seriously though, I get a bit of CA and purple fringing with that and its so easy to fix in Lightroom that it doesnt really bother me..
Message edited by author 2008-07-07 17:23:10. |
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07/07/2008 07:13:32 PM · #12 |
I belive canons' DPP will pull out/ fix CA and any number of other lens aberrations. You have to shoot RAW though (as a wedding photog you should anyway).
I have the 85 1.8 and find it a tad long so I got the 50 1.2 for weddings. I found the 50 1.8 to have really bad CA, the 50 1.2 I don't notice it at all, if its even there.
I've not heard of any wedding photogs complaining about CA on any lens really. The 70-200 2.8 is real bad shooting into the light regarding contrast killing flare but you just learn not to shoot it that way or else you'll spend a lot more time in post fixing images, or time with the customer explaining your artful interpretation of their ceremony :D
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