C.H.Ling wrote:
> I'm really interested to know what software can deal with chroma, some years
> ago people say Panorama Tool can do this and even provided a formula for
> correcting E-10's barrel distortion and chroma. Finally the distortion is
> correction but never the chroma, I suddenly remember there are color shift
> only on the bright white light area how can they correct this without
> affecting the other normal area around them?
>
> The problem of C*non lens on full frame is not only vignetting and chroma,
> the resolution is also seriously affected, I have seen their own test sample
> with the 16-35/2.8 on 1D MKII, they edges resolution was really suffered and
> it was not even FF.
--------------------------------
I've never used PhotoShop to try and correct chroma as I've never
detected any significant chroma in my own stuff. I just assumed it
could do it but I notice now that my PS v7 has no mention of it. I
assumed it could do it since I have used Picture Window to correct a
test image (maybe it was even one of yours). As I recall, it showed a
pair of escalators in a shopping mall and the bright stainless steel
areas of the escalators showed chroma. PW Pro didn't correct it
completely but made a dramatic reduction and the image looked much
better. I think I also tried one of your water images where there was
chroma visible in the highlights of the hundreds of reflections on the
waves. I'm not sure but I don't think that worked very well at all.
The PW Pro chroma tool doesn't require any information about the lens.
It simply has two sliders which adjust a shift distance (which increases
with distance from the optical axis) applied to red and blue pixels.
You watch the preview window and decide when it looks better. Pretty
simple and fairly effective I think. I'd be surprised if a later
version of PS can't do it or if there isn't at least a plug-in available
from someone.
Chuck Norcutt
http://www.chucknorcutt.com
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