And that juicy tidbit is the only good thing to come out of selling my 10-22 when I went FF. (I plan on getting a 17-40 and have an extra B+W filter lying around for it.)
You should lose very little when selling your 10-22, used, they are about the same price as a 17-40. I am not a big fan of the 17-40 on FF, but if stopped down, its fine. Perhaps mine was just a poor copy, it happens. It wasn't bad, just did not seem to inspire me.
Yeah, 17-40 fine on crop, crap on full. http://www.extremeinstability.com/stormpics/compare2corner.jpg That is F9 corner of my old 17-40 on a 5D II. Center was sharp, so it wasn't the focus being off. Thing made full frame sorta pointless.
and I can find many many more. Is it a copy issue?