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ACR chromatic aberration correction

Discussion in 'Retouching and Post Processing' started by DBrim, Jun 25, 2007.

  1. DBrim

    DBrim

    330
    May 30, 2007
    Boston, MA
    I'm correcting a photo that has about 3 px of CAs at the border in ACR 4.1. This photo has a leg of a pier with the CAs surrounding it. I went to the correction tools, and I got something resembling correct. However, there's a "halo", AKA there's a 1px section that looks correct (sky in this case), then a 1px section that resembles in inside of the section (pier leg), and then it continues as normal. What happened? Is there an automatic way to correct the CAs (a plugin or otherwise).
     
  2. I'm sure others have better ways to handle this, but since there was no responses, I'll lead off. Here's a couple of ways that I use to work on CA.

    One method I do is to locate all edges in the photo (using an edge mask). The mask must be as wide as the CA is at it's widest section. Then use color select to pick just the CA colors and desat those in the masked layer. That way only the edge gets a destat and (because you did a color select) only the CA colors are impacted.

    The other process is to use the lens correction in CS2+. BUT, I do this on a copied layer of the background. So I make a copy of the background, then use lens correction to remove as much CA as possible. It it needs to be tweaked just a bit, I'll do a minor edge desat (above). The results doing this are not very good. Image sharpness seems to be reduced a lot, so the last step I do is to change the blending of the top layer that I worked on to "color". When doing this, the CA is removed, but the image sharpness seems to remain untouched.

    If you wish to post a sample, I'd be happy to work it. If you with to see a sample of one done previously, let me know.
     
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