I beleive in Zeiss lenses, and would like to have one on my F6. It is why I spend so much time looking how they perform. ZF 100 mm macro, as I saw pictures, perform nothing so visible behind 100R Leica. However I got a brake from Cosina made. As Kuhiko from Japan, one of apuger, once stated, Cosina product are of no match to Nikon. Looks I finaly gave up on ZF lenses, not Zeiss but Cosina part. As Kuhiko said they are pin(the best)-kiri(bad), optic being pin and Cosina works being kiri. Here is what I found. http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00Lrfe I am not looking to blame anyone, especially Zeiss, I just got diappointed from the cooperant Cosina. Finaly I will clean all my house from papers about ZF lenses.