This lens was made for the Minolta SRT-101. In the 1976 Pop Photo tests of 32 lenses, it had the best center-sharp performance of SLR lenses. This one has perfect glass, was $40 at a Photorama camera show. Adapted to M-Mount using a Foto-Diox adapter ($35), the leg from a tripod, and a retaining ring from an old lens. Wide-Open, F1.4 on the M8. This lens is known for being center-sharp. A great match for the M8.