in general a dedicatedmacro lensshould deliver the best optical quality and the diopter lens should be the worst withe tubes somewhere in betweenbut I was positively surprised by the Carl Zeiss diopter for the Hasselblad.Those guys know what they are doing!I'm looking forward to check up on the idea of using enlarger lenses for close-up photography.You can get SKGrimes to make you an adaptor that doesn't break the bank but delivers superior quality with your enlarger lens(just a theory of mine at this point)