I discovered very quickly that the Pentax 645 was much easier to use than the Hasselblad 500c. I got more photos per roll, too, even though they were smaller than the 6-by-6cm of the 500c. The were/are 6-by-4.5cm, which is where the "645" comes from in the name. One thing I did notice was the clarity and sharpness of that prime lens. To my eyes, it was just as good if not a tiny bit better than the renowned Carl Zeiss Planar 80mm f/2.8 prime lens. I started shooting with the Pentax 645 a lot because unlike the 500c and the two Mamiyas, it isn't a pain to use. It acts a lot like a 35mm SLR or even a DSLR, much more so than my three other medium-format cameras.