Hi - I currently own a Mamiya 4x loupe (which I like) for viewing my 35mm and 120 slides and negs. I like being able to see the full frame, but I would like higher magnification (10x or higher) for checking sharpness,etc. I was thinking about rather than buying a separate loupe, maybe getting a zoom - like the Mamiya 4x-12x which would let me get rid of the current one I have. I haven't been able to find one at any local shops to check out in person, so I was wondering if anyone had any experience with this loupe. Other recommedations welcome. Can zoom loupes be expected to be not as good as primes (same generalities as with lenses)? Otherwise, I may just go with the Schneider 10x. Thanks.