The sharpest lens I've ever owned is the Nikkor AFD 50mm f1.8. A $25-50 lens used nowadays. The Mamiya 6, 50mm is very close but not quite there. Of course, when I print at 19 inch x 19 inch from the Mamiya it is spectacular. I've never been satisfied with anything larger than 5x7 from 35mm negatives (after I saw what the mamiya could do).