chromatic aberration

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chromatic aberration

Postby Pierre » Tue Dec 13, 2011 3:56 pm

Hi,

will be it possible to includ in next version a panel to correct chromatic aberrations ?
I agree that if we work with jpg files, we can correct them with another soft, but how can we do with raw file ?

Thanks for your very very good software !
Pierre
 
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Re: chromatic aberration

Postby Sebastian Nibisz » Tue Dec 13, 2011 4:12 pm

I'll think about how to implement this correction.
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Re: chromatic aberration

Postby Pierre » Wed Dec 14, 2011 4:40 pm

Ok, thanks :)
Pierre
 
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Re: chromatic aberration

Postby Bart_van_der_Wolf » Thu Dec 15, 2011 5:06 pm

Sebastian Nibisz wrote:I'll think about how to implement this correction.


Hi Sebastian,

Allow me give you some ideas to impove on what others have done. The usual corrections for Lateral Chromatic Aberrations (LCA) involve a radial enlargement of one or two of the color channels, in order to align all three of them if there is a poor registration. The usual simplification is to assume a radial enlargement from the image center. However, most lenses have a slight decentering of the optical elements. In addition, there are lenses, e.g. tilt and shift lenses, that allow a significant user defined decentering to use a different part of the projected image circle and which can vary from shot to shot.

So to do a better job than the competition, the solution should also automatically determine the center of the aberrations before resizing the color channels radially.

When the LCA is not corrected prior to tonemapping, then the colorful fringes may get 'enhanced' by the tonemapping and the image becomes even more difficult to correct afterwards. LCA correction is the first step, preferably even before Raw demosaicing. This is not a simple issue to solve but it can make a big difference in the individual exposures when Raw is used, or when the images were not corrected when they could have been.

If you need a sample file from my TS-E 45mm lens (which has significant CLA), and the image can also be a shifted version if you want to test your solution, just let me know by PM or e-mail.

Cheers,
Bart
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Re: chromatic aberration

Postby Sebastian Nibisz » Thu Dec 15, 2011 5:23 pm

Thank you Bart, I'll be working on implementation of this correction.
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