I gave a friend of mine an 85 1.8D as a gift portrait lens. It was new then, but it's been a couple years now. After recently buying a new body, he's discovered through careful and exhaustive testing with this and other lenses and different bodies that the lens is not sharp at 1.8, or even 2.8. It starts getting crisp at f 4.0 which makes it pretty useless as a portrait lens. Details like hair and skin are clearly soft despite how the lens is focused (MF or AF). We are both certain that this isn't a matter of operator error. Could there be some "copy variation" that would account for this? What could be wrong with it? I realize of course I could just send it to a repair center and spend additional money to "maybe" have it fixed.