I used a C33 for years in the 70's, with the 80 (or 75, whatever that range was) and the 135, always on tripod, and liked the results. But eventually I moved to Rollei's because of something I'll call a combination of sharpness and contrast that I kept seeing as better with the Rollei lenses. I often wondered, though, whether it was better optics in the Rollei, or whether the mounting and changing mechanism of the Mamiya (which I always considered to be somewhat tinker toy) resulted in not quite accurate position of the lens to film, or slight differences in the focusing vs the shooting.