A small note. I have no desire to contradict the previous comments, but PF is not CA
per se. Probably the best evidence for this assertion is that it does not happen with film cameras. I have yet to read a good explanation of the actual physics except that the general consensus is that it is due to an interaction between the lens and sensor under specific lighting conditions.
Some lenses are more prone to PF than others, but conditions such as those in wildman's first shot are typical. The classic examples:
- Specular highlights on wavelets in water
- Backlit branches
- Sunlit curved chrome surfaces
- Specular highlights on crumpled cellophane (candy wrappers)
PF is not limited to out-of-focus areas and does not go away at smaller apertures. (I can provide examples of PF for both cases.)
Unlike CA, PF is fairly difficult to correct in post-processing. At least, I have not found an easy method short of subtracting out the color in question.
Steve