Topcon Unirex

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The Topcon Unirex is a 1969-1973 SLR from Tokyo Kogaku offering TTL spot or averaging metering.

The Unirex is most unusual for a SLR in having a leaf shutter not within the lens (or between a permanently attached rear section of the lens and an exchangeable front section), but instead behind the lens, which is exchangeable in its entirety.


  • Lens mount: UV Topcon bayonet mount. The mount included a locking facility when Topcor UV lenses are attached.
  • Viewfinder: Fresnel screen with central mirco-prism focusing spot, and a fine focusing ring around this. Magnification x 0.75.
  • Shutter: Seikosha SVL leaf shutter in camera body. Speeds 1 sec to 1/500th plus B and self-timer. 1/15th to 1/500th available for auto-exposure (in red: lower speeds in black). 10 sec self-timer (set MVX switch to V, and press shutter release).
  • Meter: Open aperture needle based (f stop shown) TTL dual metering system. Two CdS cells are located either side of the viewfinder, and a third - used alone for spot metering - is located behind the mirror. Average brightness using all three CdS cells. Needle-pointer shows f-stop in viewfinder, including under and over exposure warning zones.
  • Exposure: Automatic shutter speed priority, or fully manual. Lens aperture setting ring is part of the camera body, so maximum lens aperture has to be dialled-in using a separate control (the film speed is set by aligning with the maximum lens aperture.
  • Film Speed: 25 to 1600 ASA (selector dial has a locking lever). There is also a DIN scale on the opposite side of the dial.
  • Flash: Cold shoe and PC terminal. M and X sync (set to X for daylight photography). The X setting would have also been used for class F and S flash bulbs.
  • Film Advance: Single long stroke lever (180° with 20° offset).
  • Frame Counter: Automatic count-up and reset.
  • Rewind: Via crank and bottom release button.
  • Size: 141 x 93 x 59mm (W x H x D).
  • Battery: 1 x 1.35v PX625 mercury battery (use the equivalent WeinCELL MRB625 zinc air cell).

The Unirex EE lacked the spot metering option. Both camera models were also available in black.

The replacement model for the Unirex was the Topcon IC-1 Auto introduced in 1973 or 1974 (information sources do not agree), and it's design is rumoured to have been triggered by Seiko's cessation of the Seikosha SVL leaf shutter's production, which forced Topcon to modify the Unirex to accommodate a focal-plane shutter. There were other changes too, but the two cameras certainly have a very similar appearance.