Sankyo Kohki Komura 85 mm f1.4 – Fast Vintage Portrait Lens – M42 mount
The rear has Komura’sUnidapter screw-in system, in this case thesmaller 41.75 mm variant. (Most Komura Unidapter lenses used a 46 mm thread, but a few, including the 85mm f/1.4, were made in this smaller size. ).