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DPChallenge Forums >> Tips, Tricks, and Q&A >> what is chromatic aberration?
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Showing posts 1 - 14 of 14, (reverse)
AuthorThread
10/20/2005 06:24:26 PM · #1
I am having a hard time finding out information that is understandable on the net
thanks
Leon
10/20/2005 06:29:15 PM · #2
It's an optical defect in a lens that is caused by the fact that different wavelengths (colors) of light are not focused by a lens at the same point. It manifests itself as "purple fringing" in areas of high contrast opn exposures taken at open apertures. All lenses have it to some degree it's just that some minimize it better than others.

Message edited by author 2005-10-20 18:30:43.
10/20/2005 06:32:46 PM · #3
In digital photos, you may notice "purple or blue fringing" in these types of situations:

The sky seen through tree branches or leaves; The edges of interior doors or windows where bright light is coming through; Night photos of fireworks or city lights; Photos of fluorescent light fixtures or bare light bulbs;Sun or light reflections on water; Reflections on chrome; The edges of backlit objects; Sunlit white shirts against a dark background.

Photos taken with telephoto and zoom lenses may be more prone to contain chromatic aberrations due to the way digital cameras capture light rays
10/20/2005 06:42:41 PM · #4
oooooooo, is there any way it can be prevented?
10/20/2005 06:46:05 PM · #5
Easy to post proces.
10/20/2005 06:55:39 PM · #6
post processing editing can remove it, and some lense manufacturers now make Digital only versions that try to correct the problem
10/20/2005 07:18:23 PM · #7
Here: //www.vanwalree.com/optics/chromatic.html is a good description of the effect.
All lenses will have SOME chromatic Aberration (CA), some very noticably, others hardly detectable. It can be partly compensated for by software later on, but you really need to know what you're doing to get good results with that.
As a rule, zoom lenses usually have more CA than primes of comparable quality, and "consumer zooms", those lower priced, slow lenses with very wide zoom ranges, are typically the worst.
BTW, when you see a magenta fringe on BOTH sides of a strong highlight, that's not CA, it's an unrelated effect that is not fully understood. It is also worse with some lenses than others, but typically shows up with some fast primes when shooting at wider apertures.

Message edited by author 2005-10-20 23:29:46.
10/30/2005 06:22:21 PM · #8
Hi,

Having the same problemm with my new quanteray 70-300mm and was just going to start a thread but saw this one - hope no one minds me asking the following: does anyone know if it can be fixed easily in Photoshop elements 3.0 and if so, where would I find it? Or, is this such an inferior lens that I should return it and wait and buy a new one?
thanks
10/31/2005 02:25:28 AM · #9
Originally posted by BJ:

Hi,

Having the same problemm with my new quanteray 70-300mm and was just going to start a thread but saw this one - hope no one minds me asking the following: does anyone know if it can be fixed easily in Photoshop elements 3.0 and if so, where would I find it? Or, is this such an inferior lens that I should return it and wait and buy a new one?
thanks


In Camera Raw in photoshop there is a tool to fix this, very easy to use, but works only on RAW format
10/31/2005 02:52:01 AM · #10
Are you using web search engines like Google? I entered chromatic aberrationand got some really clear descriptions of it.
I also use online enciclopedias, for example //www.en.wikipedia.org
10/31/2005 03:20:05 AM · #11
Originally posted by LEONJR:

oooooooo, is there any way it can be prevented?


Yes; buy "L" glass :-)

Robt.
10/31/2005 03:49:00 AM · #12
Originally posted by bear_music:

Originally posted by LEONJR:

oooooooo, is there any way it can be prevented?


Yes; buy "L" glass :-)

Robt.


Ever tried the 85L in high contrast scenes? I know.. It's a pretty extreme lens. Just saying, that even the most expensive L lenses can have quite a bit of CA. But of course you already know that.
10/31/2005 04:22:39 AM · #13
Originally posted by Uusilehto:

Originally posted by bear_music:

Originally posted by LEONJR:

oooooooo, is there any way it can be prevented?


Yes; buy "L" glass :-)

Robt.


Ever tried the 85L in high contrast scenes? I know.. It's a pretty extreme lens. Just saying, that even the most expensive L lenses can have quite a bit of CA. But of course you already know that.


Yah, I know... It's a fact of photographic life. I was just havin' some fun...

Robt.
10/31/2005 05:59:59 AM · #14
Originally posted by apiras:

In Camera Raw in photoshop there is a tool to fix this, very easy to use, but works only on RAW format

Yeah, blows my mind how effective (and easy to use) this tool is.
Another good reason for me to shoot RAW as I do experience this problem regularly with my inexpensive lenses - especially in very bright scenes.
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