Mamiya's upgraded 645 SLR — 1/1000 focal-plane shutter, preview, self-timer, 1976.
The Mamiya M645 1000S is a mid-1970s medium-format SLR, an upgraded version of the M645 in Mamiya's 6x4.5 system. Its main additions were a faster top shutter speed, a depth-of-field preview, and a self-timer, making it the more capable of the early 645 bodies.
It is a medium-format (6x4.5) SLR producing a 56x42mm frame on 120 or 220 film. It uses a body focal-plane shutter with a top speed of about 1/1000 second, which gives the model its name. It takes interchangeable waist-level or prism finders and focusing screens and mounts Mamiya 645 bayonet lenses; a metered prism finder can provide TTL metering. Film is loaded via inserts rather than fully removable magazines.
The higher top speed, preview, and self-timer made the 1000S more flexible than the base M645 for portrait, wedding, and general work, especially in bright light or with faster lenses. It keeps the lighter 645 handling that made the system approachable for photographers moving up from 35mm.
Test the focal-plane shutter across speeds, including the top speed, for accuracy and even travel, and confirm the film insert and its seals. Check the depth-of-field preview and self-timer, the mirror, screen, and finder mirror, and any metered prism against the correct battery. Foam light seals commonly perish and should be inspected.