Japanese medium-format SLR (edit)
6×9 Rittreck (6×9)
6×8 Fujifilm GX680
Japanese TLR and pseudo TLR ->
Other Japanese 6×6, 4.5×6, 3×4 and 4×4 ->

The Zuman Flex (ズマンフレックス) is a Japanese SLR using 120 film, briefly advertised in 1951–2 by Zuman Kōki Kenkyūjo, later Zuman Kōki Seisakusho. It is said that it remained at the prototype level.[1]

The original Zuman Flex[]


The original Zuman Flex was advertised in the September 1951 issue of Kohga Gekkan, with no price indicated.[2] It was presented together with the Zuman Super 16. No other occurrence of the camera is known in the Japanese magazines.[3]


No surviving example of the Zuman Flex is known so far, and the following description is based on the picture of the advertisement, taken from the front left side.

The camera takes fourteen 5×5.5cm exposures on 120 film. It has a brick-shaped body, containing the vertically running rollfilm and a focal-plane shutter with metal curtains, giving B, 1, 2, 5, 10, 25, 50, 100, 200, 300, 450, 600 speeds. The camera can take stock lenses from 75mm to 150mm focal length, and the standard lens mentioned in the advertisement is a Zuiko 75/3.5 by Olympus. It seems that the lens is mounted on a square board, itself attached to a front standard which moves back and forth for focusing. Some sort of long button is visible above the lens board; it is perhaps used to detach the board from the front standard.

There is a wide knob on the photographer's left; it is not known if it is used to set the shutter speed or to focus the lens. The auto-stop film advance is coupled to the shutter winding, and there is an exposure counter and double exposure prevention. It is not known if the original model has the same advance crank as the later Zuman Flex M; the film advance is certainly on the photographer's right anyway. There is a lever visible at the top left of the body, above the speed selector; this is perhaps the shutter release. The shutter is synchronized at all speeds but the position of the synch post is unknown.

The viewing hood is non interchangeable, but its centre part is perhaps retractable, giving place to a sportsfinder. The name Zuman flex is written in front of the viewing hood, above the movable front standard.

The Zuman Flex M[]

The Zuman Flex M is an evolution of the previous model. It was advertised in Japanese magazines from May to November 1952.[4] The July advertisement in Kohga Gekkan oddly mentions 14 exposures in 6×6cm format.[5] The advertising picture is taken from the front right, and shows minor differences with the previous model. The sportsfinder looks larger and squarer than before; this could be a hint of a new 6×6cm picture format. The lens board has a more rounded shape and has no button above. The nameplate reads ZUMAN FLEX in uppercase letters.

The advertisement mentions some features which were not announced for the original model and might be specific to the Zuman Flex M, namely an automatic diaphragm, a crank advance and a special device for maintaining the film flatness.[6] The shutter has an added T setting and the shutter and mirror are presented as vibration-free, perhaps because they were improved since the original model.

No surviving example of the Zuman Flex M has been observed either.


  1. Prototype only: Lewis, p.76.
  2. Advertisement reproduced in Kokusan kamera no rekishi, p.143.
  3. Kokusan kamera no rekishi, p.353.
  4. Kokusan kamera no rekishi, p.353.
  5. Advertisement reproduced in Kokusan kamera no rekishi, p.143. The camera is called "Zuman Ref M" (ズマンレフM型): the word "Ref" was commonly used instead of the ending "Flex" in Japan at the time.
  6. Lewis, p.76, says that the Zuman Flex has preset aperture, but does not precisely say which model is described.


The Zuman Flex is not listed in Sugiyama.


In Japanese: