The MDN Camera The MDN unit, a grip, a viewfinder, a film magazine, and a lens are the five modules that come together to become the actual MDN camera. The uniqueness of the MDN camera was in its form that completely differed from conventional 35mm SLRs.
The official Olympus OMD group posted this tribute post for the Olympus MDN:
How many of you have heard of the MDN? The MDN was the centerpiece of a prototype modular 35-mm camera system called the M-System developed by legendary Olympus engineer Yoshihisa Maitani. The idea was that you could combine the MDN camera unit with modules of your choice, including viewfinder modules, lens modules, motor drive modules, and film magazine modules, depending on your needs.
It was actually the MDS unit, a simplified version of the MDN, that later evolved into a camera we all know as the OM-1. Development of the OM-1 was prioritized over the development of the M-System, and the M-System ended up never making it to the market.
However, it was the advanced M-System prototype that helped make the OM-1 overcome common SLR issues such as being big and bulky, heavy, and prone to shutter shock. And it was the various motor drives, macro units, etc., that paved the way for the OM-1’s full camera system rich with accessories. In such ways, the origins of the OM-1 can be found in the modules of the M-Systems. Read the descriptions of each individual image to find out more.
The M-System This initial drawing of the M-System concept was made my Maitani himself, on January 8, 1969. Just to the right of the center you can find the MDN unit, and next to it is the MDS unit, which later evolved into the OM-1.
Film-winding Units Front: Manual winding unit. Left: Spring-driven winding unit. Rear: Electric auto-winding unit.
MDN Camera Unit – Front View You can see here that the MDN unit was equipped with a mirrorbox inside and a shutter speed ring around the lens mount, all in a super-compact package. Keeping a fully functional unit light and small was very important to Maitani, and this trait was carried on in the OM-1.
MDN Camera Unit – Rear The shutter is a cloth focal plane shutter, also employed on the OM-1, overcoming the issue of shutter shock experienced by conventional SLRs of the time.
Film Magazine Notice the shot count goes up to 72, indicating that Maitani had half-frame photography in mind.
Viewfinder Although there were several viewfinder options planned for the M-System, this is the only M-System viewfinder prototype that exists in the Olympus archives today.