500D/550D with L - lens

[lioneldude]

You would find that most L lenses are much sharper than used on full frame bodies. Cause the little softening at the corners have been cropped away. So overall you get extremely sharp pictures. But keep in mind, L lenses are mostly sharp throughout the whole picture. So effectively, its like buying an expensive sports car, but you cant go above the speed limit of 90km/h.

Hmm, hope this analogy helps

well said.

On full frame, corner sharpness may be poorer since it uses the edge of the lens, you may stop down 1 or 2 f-stops to improve sharpness. However, since most of the time, you won't be printing bigger than A4, is poor corner sharpness that important? There are other ways to work around corner sharpness, eg you wouldn't frame your portrait model's face in the corner of the frame for most conventional shots wouldn't you?

 

[night86mare]

i think corner sharpness is not really that important.

i'd wager 80% of the time, you will not need extensive sharpness/detail in the corners, since placing elements there (at least important ones) would serve more as a distraction than anything else.