Mamiya 150mm f5.6 Sekor - Lens

Mamiya made a series of industrial rangefinders starting in 1960. These cameras were intended for press photography and featured interchangeable backs, leaf shutter lenses, and various grips and accessories to improve handling.

The first few models could only accept either Mamiya or Graflex film backs without adapters, but the final model (Mamiya Universal) can accept either as well as a Polaroid back.