The Mamiya 120mm f/4 Macro A (645 medium format mount) is a manual focus macro that produces 1:1 life size macros. Its “A” signifies that its an APO (Apochromatic) lens using low-dispersion glass, which is optimized for color correction and spherical aberration. Aperture ranges from f/4 to f/32 - which gives it a large depth-of-field. This is one VERY sharp lens - even at f/4. I use mine with a Fotodiox Pro Adapter fitted for my Canon bodies.