i was thinking about this the other day. I love looking at the many images posted on the forum. Every once in awhile there is one that has something special about it. It isnt sharpness, though that is part of it. There seems to be a richness to the color....something other than just saturation. Is it contrast, is it clarity? We always think of sharpness as a prime definition of a great lens, but there is more to it than that isn't it? What's the quality that makes a lens great? Caveat, yes photographer, scene, light, etc.. All have more to do with it, but some lenses seem to get the most out of a shot?