Canon 50D vs Nikon D90: In-camera CA Reduction – Andy Westlake, in response to a question on the excessive CA in this Canon 50D photo, and about the comparisons between the sample photos posted from both cameras:
Canons don’t have in-camera CA correction, this is only available when shooting RAW and processing in DPP (and then only for profiled Canon lenses). The 50D does however have vignetting correction built in.
This in fact is one area where Nikon are well ahead; the D90 has auto CA correction on all lenses, vignetting correction, and even adds distortion correction (profiled for known Nikon lenses) in the retouch menu.
Auto CA correction has a significant impact, as it also improves overall IQ towards the corners substantially, and is probably one of the main reasons the D90’s JPEGs look so good.