Japanese Semi (4.5×6)
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The Rocky Semi (ロッキーセミ) is a Japanese 4.5×6 folding camera made by Umemoto and distributed by Endō in 1953–4.

Possible wartime predecessor[]

There are some hints that Umemoto made a 4.5×6 folder called Semi Makinet from 1941. Umemoto Hideo, son of Umemoto Kinzaburō, founder of the company, testified that rather large dies salvaged from the destruction of the Kameido-machi plant during the bombing of Tokyo in 1945 were stocked and perhaps re-used for the Rocky Semi.[1] They were perhaps the press dies for the Semi Makinet body.


According to Umemoto Hideo, the Rocky Semi was completed and sold in 1953.[2] The camera was featured in the May 1954 special issue of Photo Art about folders. The column, reproduced in this page, is the only original document known so far to mention the camera.[3] It confirms that the Rocky Semi was distributed by Endō Shashin-yōhin for ¥8,300.[4]

Unfortunately no complete example of the Rocky Semi is known to have survived. An unfinished body shell and two lens and shutter assemblies are currently preserved by Umemoto Seisakusho and are displayed in the company's history page.

Description of the body[]

The Rocky Semi is a vertical folder and has a pressed steel construction. The overall aspect is not unlike that of the contemporary Zenobia. The viewfinder is contained in a top housing, and is slightly offset to the right — as seen by the photographer holding the camera horizontally. The folding bed release is on the right, the main body release is on the left, and there is an accessory shoe to the left of the viewfinder. The film advance knob is at the left end, next to the body release; the right end has a dummy knob or perhaps a rotating depth-of-field scale. The back is hinged to the left and has a single red window, protected by a horizontally sliding cover.[5] The name ROCKY is embossed in capital letters in the front leather.

It seems that the pressed steel construction was adopted for cost reasons. Around 1951, Umemoto Kinzaburō visited the company Tanaka Daikasuto (田中ダイカスト, meaning Tanaka Diecast) which made the body castings of the prewar Super Makinet Six and Super Flex Baby, but the price of making a new diecast body was too elevated.[6] It is supposed that it was chosen instead to reuse the press dies dating from the Semi Makinet.

Lens and shutter equipment[]

The column in Photo Art mentions a Rocky 75mm f/3.5 front-cell focusing lens and an MSK shutter giving B, 1–200 speeds, and equipped with a self-timer.[7] The picture faintly shows the lens engraving ROCKY Anastigmat 1:3.5 F=75mm No.xxxx and the lens number 1000 or 1004. The numbering sequence certainly started at 1000 or 1001, and the pictured camera was one of the first assembled examples.

The MSK shutter was the standard equipment for the Rocky Semi, and was made by a company called Shibayama.[8] It was also mounted on some Mihama cameras; it has the name MSK engraved at the bottom of the speed rim and an ASA synch post at the top.

The two lens and shutter assemblies pictured in the company's history page were found by Umemoto Akio (grandson of Umemoto Kinzaburō); it is supposed that they were intended for the Rocky Semi. Both lenses are engraved NITSUKO Anastigmat 1:3.5 F=7.5cm No.xxxx; they have very close serial numbers (1347 and 1349). No Nitsuko lens is known on any other camera, and it is not known why the Rocky lens name was dropped.

Lens no.1347 is mounted on an MSK shutter, the same as pictured in Photo Art. The other shutter is a TKS made by Tōsei Kōki. It gives B, 1–200 speeds, has a self-timer and a single synch pin. The name TKS is engraved in capital letters at the bottom of the speed rim, and the shutter plate has a pattern of black and white triangles and the word TOSEI at the bottom. This particular shutter type is normally found on the Frank Six Model I; it was perhaps considered to make a batch of Rocky Semi with this TKS shutter, but nothing is known for sure.

These two spare units were certainly among the last made for the Rocky Semi. According to the testimony of Umemoto Hideo, the company made a single batch of cameras before stopping the production.[9] From the lens numbers, the total production can be estimated at about 350 units.


  1. Umemoto company history.
  2. Umemoto company history.
  3. It is notably the only document listed in Kokusan kamera no rekishi, p.375.
  4. These data are also mentioned in the testimony of Umemoto Hideo.
  5. This is visible in the surviving body shell pictured in the company's history page.
  6. Private communication to User:Rebollo_fr by Umemoto Akio, son of Umemoto Hideo and grandson of Umemoto Kinzaburō.
  7. Kokusan kamera no rekishi, p.375.
  8. Standard equipment for the Rocky Semi, made by Shibayama: private communication to User:Rebollo_fr by Umemoto Akio, grandson of Umemoto Kinzaburō, the founder of the Umemoto company.
  9. Private communication to User:Rebollo_fr by Umemoto Akio, son of Umemoto Hideo and grandson of Umemoto Kinzaburō.


  • Asahi Camera (アサヒカメラ) editorial staff. Shōwa 10–40nen kōkoku ni miru kokusan kamera no rekishi (昭和10–40年広告にみる国産カメラの歴史, Japanese camera history as seen in advertisements, 1935–1965). Tokyo: Asahi Shinbunsha, 1994. ISBN 4-02-330312-7. Item 1054. (Unlike most other entries in this book, no advertisement is reproduced and no picture is given.)
  • Photo Art rinji zōkan: Supuringu kamera zensho (フォトアート臨時増刊・スプリングカメラ全書, Photo Art special issue: All the folding cameras). May 1954, no.65 of the magazine. "Supuringu kamera depāto: Kokusan" (スプリングカメラデパート・国産), article on Japanese folders, pp.43–54.

The Rocky Semi is not listed in Sugiyama.


In Japanese:

Umemoto cameras
6×6 strut folders 4×4 SLR 4.5×6 folder
Super Makinet Six | Neure Six Super Flex Baby Semi Makinet | Rocky Semi