1 Reply Latest reply on May 8, 2008 2:00 PM by (Jeff_Schewe)

    Do color samplers work with chromatic aberrations?

      Has anyone tried to use the color samplers in ACR 4.4 for calibrating chromatic aberrations? The sampled values near the image boundary seem to change as I adjust lens vignetting (as expected), but values sampled at high contrast edges do NOT seem to change as I adjust fringing parameters (not expected).

      Assuming this doesn't work (either by Adobe's design or by oversight), how do folks accurately neutralize fringing using these controls? Simply by eye?
        • 1. Re: Do color samplers work with chromatic aberrations?
          Level 1
          >how do folks accurately neutralize fringing using these controls? Simply by eye?

          Hold down the option (Mac) or ALT (Windows) when zoomed to 400% at the corners...the option/alt keys default the preview to be either the Red/Cyan or the Blue/Yellow fringe. Makes it easier to address them one at a time.

          Also, your lenses will tend to behave in consistent mannersfor example on my Canon wide angle zooms I usually need a -20 to -30 in Red/Cyan with a lesser amount in Blue/Yellow. Occasionally, the Blue/Yellow may go a little bit in the + direction (I don't recall EVERY going + with Red/Cyan). From these general guidelines (not the specific numbers) all I need to do is adjust for the strength of the CA.

          Also note that along very high contrast edges, you may NEVER be able to correct the CA because the effect of the finging isn't coming from CA but from photo site blooming. In that case, use the Highlight Edges DeFringe option.