The Mamiya 645 Pro is a medium-format SLR camera introduced in April 1992 by Mamiya in Japan. It makes fifteen 6x4.5 cm images on 120 roll film and features a polycarbonate body. Unlike its predecessor, the 645 Pro lacks a mechanically-timed shutter speed, meaning it requires battery power to operate. It uses the same bayonet lens mount as earlier M645 models, and film inserts are interchangeable. The camera's manual highlights several features, including a 'T' exposure when using the self-timer with the shutter dial set to 'B', and automatic setting of the camera's focal-plane shutter to 1/8 second when using leaf-shutter lenses.