Ed- I don't know about sharpness - that's actually never been a huge concern of mine as I've never enlarged anything to the point that resolving power intrudes into image quality. What I specifically mentioned was optical correction for distortion. I probably shouldn't have even mentioned it because I see it's started another "my gear is better/sharper/more rectilinear than yours". In reality, nobody sells photographs of lens resolution test charts, so the only people who are actually impressed by this data are other photographers, which really means this is just another penis-comparison contest.