The Domirex is a 35 mm SLR camera shown as a prototype by Konishiroku in the early 1960s, but apparently never produced for sale. It has an unusual viewfinder system, without a moving mirror. The design is roughly contemporary with the Canon Pellix (which was however, made and sold). In the Domirex, two small angled mirrors are placed within the lens; these are off-axis, one to the left and one to the right. They deflect a small fraction of the light into the viewfinder system. The mirrors are placed between the lens elements, so the focusing power of the rear elements is replicated in the viewfinder optical parts. The finder would also include a rangefinder 'wedge' element (the patent describes several options, providing a central RF spot, and/or full-frame 'microsprism' focusing; it is not suggested that these elements would be interchangeable).
To accommodate this system, the iris diaphragm and the leaf shutter are mounted behind the rear lens element.
The system has the disadvantage that focusing must be performed using only a small fraction of the available light.
- US Patent 3274912, Single-lens Reflex Camera, filed by Tadashi Kasahara for Konishiroku in 1962 and granted in 1966, at Espacenet, the patent search facility of the European Patent Office. The patent shows diagrams of the camra, and describes various options for viewfinder focusing.
- Konica Domirex at JJ's Le Système Reflex Konica (text in French; archived at archive.org in 2018).
- Hishida Kōshirō (菱田耕四郎). "Konica History 11: Maboroshi no kamera to tokushu kamera" (幻のカメラと特殊カメラ, Phantom cameras and special cameras). Kamera Rebyū: Kurashikku Kamera Senka (カメラレビュー クラシックカメラ専科) / Camera Review: All about Historical Cameras no.10, September 1987. No ISBN number. Konishiroku kamera no rekishi (小西六カメラの歴史, special issue on Konishiroku). Pp.81–2.