Talk:Chromatic aberration
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[edit] Purple Fringing isn't CA?
In digital photography it is common to see color fringes around high contrast areas. Imagine a dark spot against a light background. Chromatic aberration in the main lens of any camera (digital or otherwise) is caused because the wavelengths of light refract through the lens at slightly different angles, causing the "red" part of the image to be displaced from the "green" (say), leaving a red fringe to one side of the dark spot, and green fringe on the opposite edge.
Purple fringing is usually used, in my experience as a professional photographer, to refer to a separate artifact in which all sides of the spot I described above would have a fringe of the same color, but the source of that particular type of error would seem to be somewhat different than what's usually meant by "chromatic aberration."
Lacking citations, I'm making no changes to the text, but I encourage interested authors to consider and if appropriate apply the distinction I'm making.
[edit] CA's are Color fringing caused by objektiv=====
purple fringing is the same as transversal cromatic aberration which must not always have more than one smudged colors. In most cases it overlays with longitudinal cromatic aberration and has an expression in different magnification for example green fringing.
[edit] CA is always in pairs of colours
Which you can actually see in the examples. 'Real' optical CA is a violet edge on one side of a sharp detail, and red on the other side. The graph on the bottom explains why those pairs are red and violet. Opposite ends of the spectrum The top-image has a purple/green fringing, which would be caused by a YUV-based video-system with an phase-error somewhere in the UV-processing. The top-image shows an video-error, not optical CA.
[edit] Mirrors
Do mirrors show CA? —Preceding unsigned comment added by 130.194.13.105 (talk) 03:57, 8 November 2007 (UTC)
Someone would have to confirm this - but I believe that the reason why CA works on lenses and telescopes is because of their refractive qualities. Since a mirror is a reflective quality only, CA shouldn't be an issue. Or if it is, then it's called something else.
Absolutely not, Mirrors don't suffer from Chromatic Aberration since they don't refract light, mirrors reflect light; this was proven centuries ago by Isaac Newton, and is the reason modern telescopes (including the Hubble telescope) use Mirrors.
[edit] Chromatic Aberration in Photography
I noticed a large part of the article is dedicated to effects of CA in photography, this is great as CA affects photography but the article (in my opinion) must show the causes of chromatic aberration before discussing its effects, so I'm gonna move the two paragraphs dedicated to photography and even digital cameras in the intro to a new sub-title called "Chromatic Aberration in Photography", the paragraphs may look out of context so anyone with deep knowledge on photography and chromatic aberration effects, please edit it, try to include technical data on how digital cameras correct some of this problems, should be interesting. —Preceding unsigned comment added by 189.163.205.77 (talk) 05:05, 4 March 2008 (UTC)
