Canon X-ray camera
Canon, while still named Seiki Kōgaku, made a 35mm camera for recording images on the fluorescent screen of an X-ray machine. This camera is quite simple, not needing some of the features of a camera for ordinary photography. It has no shutter; just a metal dark slide in a slot in the top plate (actual exposure would presumably be controlled by the time the X-ray source was activated/uncovered in the X-ray instrument). It has knobs to advance and rewind the film. A short length of chain is wound around the advance knob, and through a metal guide at the front: this allows the film to be advanced (perhaps just one frame) by pulling a string attached to the chain: the operator would use the camera from behind a protective screen as far as possible, to avoid exposure to X-rays. It is interesting that the Canon camera has this feature, when the wartime examples of the (otherwise very similar) Rokuoh-Sha Rubicon have a simple winding key. The earliest examples seen have a 25x32mm frame (the length of the first Nikon rangefinder camera frame),[1] and the examples of that cited below are two camera bodies with serial numbers almost a thousand units apart, suggesting many were produced with this frame size. Later bodies have a 25x26mm frame, the same as the Rubicon.[2]
The camera forms part of a kit: two camera bodies, the lens, and some reusable film cassettes. There is little difference between the Rokuoh-Sha outfit and the Seiki. Both the camera body and the kit are also very similar indeed to the 1950s Mamiya X-30, which was in fact supplied with Canon film cassettes for some of its time. It seems very likely that the design was shared, or even specified by the government. The lens for the earlier outfit cited is a Nippon Kōgaku (Nikon) Regno-Nikkor 5cm f/2, in Nikon rangefinder bayonet mount, with an adapter.[1] The lens in the later outfit cited is Seiki's own R-Serenar 5cm f/1.5 'R' presumably for Röntgen).[2] This lens was made for this job, and has no iris diaphragm or focusing (the Nikkor has an aperture ring). The lens is mounted in a short cone-shaped cowl, which would fasten over the fluorescent screen. The camera body attaches to the rear of the lens with a wide bayonet fitting. Examples may be seen which have been converted to a 39mm thread-mount by 'bokeh' enthusiasts.
After the War, these cameras were exported. A US brochure from around 1956 (the Canon VT is the newest model shown) offers X-ray camera kits. Sadly the brochure gives no more detail than For photographing X-ray images on the fluorescent screen, Canon makes two kits of X-ray camera.[3]
Notes
- ↑ 1.0 1.1 X-Ray camera outfit (described as a prototype by the auctioneer) comprising camera bodies serial no.s 1146 and 2111 with 32x25mm frame, and with 5cm f/2 Regno-Nikkor lens serial no.141138 in Nikon rangefinder mount with a mount-adapter to fit the conical instrument cowl, film cassettes and outfit case. Offered for sale at the 44th Leitz Photographica Auction, in June 2024. It may be seen in the photographs that the dark-slides are captive; they do not pull out completely.
- ↑ 2.0 2.1 X-ray camera kit sold by Christie's in May 2006: two camera bodies, serial no.s 2381 and 2382, with R-Serenar 5cm f/1.5 serial no.3092 in instrument cowl, and with two film cassettes, in outfit case. The auctioneer notes the camera is engraved (in Japanese) Seiki Optical Industry Co. Ltd. X-ray Indirect Photographing Device Army Noborito Laboratory. No 2 Section. No. 4 Group. and notes that the Noborito Laboratory operated in Kanagawa between November 1937 and August 1945. Japan was already at war with China (which was supported by the western Allies) since July 1937.
- ↑ Canon System of Photography brochure, about 1956, reproduced at Pacific Rim Camera. Oscilloscope, radar and X-ray cameras are discussed on p.31.
