Japanese Semi (4.5×6)
Prewar and wartime models (edit)
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Japanese SLR, TLR, pseudo TLR and stereo ->
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The Semi Prux (セミ・プラックス) is a Japanese 4.5×6 folding camera. It was made from 1938 by Proud-sha and perhaps Miyoshi Kōgaku, two companies which were related and certainly merged after some time. Its successor was the Roavic by Miyoshi.


The Semi Prux is a horizontal folder. Its general design and folding struts are copied from the Duo Six-20 by Kodak AG. There is a folding optical finder in the middle of the top plate, with the folding bed release immediately to the right. The advance key is at the top left; it has an angular shape and is attached to an octagonal knob. The back is hinged to the right and has two red windows near the bottom, protected by a horizontally sliding common cover. The back latch is covered by a leather handle. The name SEMI PRUX is embossed in the front leather.

Original documents[]

The Semi Prux was featured in the November 1938 and February 1939 issues of Asahi Camera, and was advertised in 1939 and 1940.[1] In advertisements dated May and June 1939 and February 1940, the camera is offered in two versions:[2]

  • U.L.L. f/4.5 lens, Licht shutter by Seikōsha (¥65);
  • U.L.L. f/3.5 lens, Prux shutter, T, B, 5–200 speeds (¥80).

The Semi Prux is presented along with the Semi Proud, as "the two favourite Japan-made cameras" or "the two authorities on Japan-made cameras".[3] The distributors are Yamashita Yūjirō Shōten of Tokyo and Fukada Shōkai of Osaka. The June 1939 and February 1940 advertisements also show the two company names Proud-sha and Miyoshi Kōgaku. The cheapest version also appears in an October 1939 advertisement by Fukada, together with Doris and Prince models.[4]

The camera is also mentioned in the official list of set prices compiled in October 1940 and published in January 1941, as the "Prux", for ¥62 with no further detail.[5]

Actual examples[]

The example of the Semi Prux pictured in Sugiyama looks the same as on the advertising pictures.[6] It has a Licht shutter (25, 50, 100, B, T) with a simple "needle self-timer". Its lens is engraved U.L.L. Anastigmat 1:4.5 f=7.5cm No.10254.

Another camera, perhaps corresponding to a Semi Prux but not identified for sure, is known with some minor changes: the folding bed release is to the left, there is a body release to the right of the viewfinder, the top plate is leather covered and the back latch seems to have a different design, with no handle.[7] This camera has a Kikō C shutter (150, 100, 50, 25, B, T), inscribed KIKŌ C on top of the shutter plate, and a Lucomar Anastigmat 75mm f/4.5 lens, both made by Kigawa.


  1. Kokusan kamera no rekishi, p.340.
  2. Advertisements in Ars Camera May and June 1939, reproduced in Fujishima, p.24 of Camera Collectors' News no.42; advertisement in Asahi Camera February 1940, reproduced in Kokusan kamera no rekishi, p.90.
  3. Translation of "國産カメラの二大寵児" and "國産カメラの二大権威".
  4. Advertisement in Asahi Camera, reproduced in Kokusan kamera no rekishi, p.91.
  5. "Kokusan shashinki no kōtei kakaku", type 3, section 3A.
  6. Example pictured in Ikeuchi, p.19 of Camera Collectors' News no.41 and in Sugiyama, item 1238.
  7. Example observed for sale by a Chinese dealer.