Mamiya-Sekor c 150 mm f/4

Mamiya Sekor SF C 150mm f/4-soft lens with a constant focal length for medium-format SLR cameras Mamiya RB.

The soft effect is achieved by replaceable diffusion discs.
Disks- https://wonderfoto.ru/katalog/fotoapparaty/plenochnye-kamery/sredniy-format/nabor-diafragm-soft-foku...