Mamiya Rapid Omega 100

Documentation on the Mamiya Rapid Omega 100 is thin. No production years, no original price, no official spec sheet survives in the record. What we know comes mostly from classified listings and collector sightings, and even those are fragmentary. One Russian listing calls it the tool of "Japanese criminalists" (forensic investigators) and says it is an extremely rare medium-format camera in working condition. A Flickr caption from a collector who spotted one at an antique store for $150 backs up the rarity claim and says that unit, fitted with a 220 back, "works fine."

Here is what is documented. The Rapid Omega 100 is a 6×7 cm manual rangefinder camera with interchangeable optics, fitted with a 90/3.5 Super Omegon lens. The shutter is a focal-plane type. One source describes it as a combined spring-mechanical unit with a clockwork mechanism for accuracy at long exposures. Speeds run from 1 to 1/500 second. The viewfinder is a combined rangefinder-viewfinder with illumination for low-light work. Past that, the record goes quiet. One Flickr user documented a home-made camera built around a broken Rapid Omega 100 body, so at least one 100 got cannibalized for parts.

Known specs, such as they are:

Medium format, 6×7 cm frame on 120 film (220 back seen on at least one example)
Interchangeable lenses; equipped example: Super Omegon 90/3.5
Focal-plane shutter, 1–1/500 sec, spring-mechanical with clockwork timing
Combined rangefinder-viewfinder with low-light illumination

Observed prices: 4,200₽ on a Russian classified site (as of April 2019) and $150 at an antique store. One eBay listing appeared "untested, as is." If you own one or have factory literature, the archive would welcome the details.