Mamiya Medium Format Lenses | Mamiya 90Mm F/3.8 Sekor Nb Lens For Rb67 {77}

Nb Designation Refers To The New Barrel Design. This Change Ocurred Very Early In The Rb Lens History And Refers To A Change In The Barrel Design That Occured In Late Non-C Lenses And Some Early C Lenses.The Early Shape Of The Lens Barrel Was Beveled At The Base Towards The Lens Mount; This New Barrel Is Straight.