Originally Posted by Jon Ruyle
I don't think it's minimal at infinity, but rather minimal within the depth of field, and stars are in focus at infinity. Put another way, the effects of CA are magnified by defocusing. They will still be there, and might be strong enough to affect the image in a demanding application like astrophotography. Also, I really don't want to contribute in any way to KR being right - I always prefer empirical data, so I hope you get a chance to test it! Technically, calling it all CA is a misnomer, since aberrations formally affect only the focused part of the image. But I think it's fair to count CA of OOF light as an aberration since the OOF parts of the field also contribute to the final image (in photography, at least - in microscopy we use tricks like confocal pinholes to optically remove OOF light, or deconvolution to algorithmically remove it).
Liar!! []
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