The auto Mamiya Sekor 50mm f2 is a 70's lens with an m42 mount. Like most 50mm's of that era, it is well made. Focus dampening is excellent. Optics are excellent from f3.5 up. At f2 and f2.8 it is a bit soft. Color rendition is neutral and accurate. Bokeh is smooth. Shadow detail is excellent. Contrast is consistent at all apertures. Flare is present if you point it directly into the sun. Images from this lens have nice depth which is reminiscent of a Mamiya TLR's image rendition.