K.O.L. and Sun lenses in Leica screw mount

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The Japanese company Gojō Kōki Seisakusho began making lenses during World War II for the Nippon Leica copy. Lenses in Leica screw mount were continued after 1945 by the company Sun Kōki, until well into the 1950s.

K.O.L. Xebec, Sun Xebec and Sun Sophia 5cm f/2

Gojō Kōki Seisakusho made the K.O.L. Xebec 5cm f/2 six-element collapsible lens for the Nippon Leica copy.[1] The lens barrel is copied from that of the Leitz Summar. The focusing ring is graduated in metres and has a tab with an infinity stop.

Two main versions of the barrel are known. The "first" barrel has the infinity stop at 10 o'clock (as seen from the front), the word Mtr in small characters and depth-of-field indications for apertures from 2 to 9.[2] Its finish seems quite poor, according to the pictures and to the comments of Mori Ryōsuke.[3] The "second" barrel has the infinity stop at 7 o'clock, the word mtr in larger characters, depth-of-field indications from 2 to 12.5, and a seemingly better finish.[4] The aperture ring is graduated from 2 to 9 on at least some lenses, even those with the second barrel.[5] The lens barrel was probably gradually improved, and the repartition of the first and second barrels do not follow the serial numbers.

The earliest known lens reportedly has no.34688; it is said that it was originally not rangefinder-coupled, and that a coupling cam was added to it later.[6] Other lenses have numbers in the 66xxx, 70xxx, 75xxx and 77xxx ranges.[7]

The lens was renamed Sun Xebec 5cm f/2, certainly when Gojō became Sun Kōki after 1945. A single example is known, with no.77818.[8] It has the second barrel, and its aperture scale goes from 2 to 12.5.

The Sun Sophia 5cm f/2 was certainly an evolution of the Sun Xebec. A single example is known, with no.72715.[9] The barrel has some similarity to the second barrel found on the Xebec, but it looks heavier and more recent. (The lower serial number is unexplained.) The front element is more recessed than on the Xebec, and the optical design was perhaps altered.

Notes

  1. ↑ Six elements: advertisement for K.O.L. lenses reproduced in Inoue, p.132, and in Hagiya, p.179 of Sekai no Raika renzu. The lens is mentioned as made by Gojō in the "Kokusan shashinki no genjōchōsa" ("Inquiry into Japanese cameras"), lens item Ja1.
  2. ↑ First barrel visible on lens no.34688 pictured in Mori, p.101, and on lens no.70067 pictured in HPR, p.260.
  3. ↑ Mori, p.100.
  4. ↑ Second barrel visible on lens no.66429 pictured in HPR, pp.258–9, and on the Sun Xebec no.77808 pictured in Mori, p.101.
  5. ↑ Aperture ring from 2 to 9 confirmed on lens no.34688 (first barrel) pictured in Mori, p.101, and on lens no.66429 (second barrel) pictured in HPR, pp.258–9.
  6. ↑ Mori, p.100. This lens is pictured and tried on pp.101–3 of the same source, and one of the pictures is reproduced in this page of Akiyama Michio's Red Book Nikkor.
  7. ↑ Lens numbers reported in Mori, p.97. No.66429 is pictured in HPR, pp.258–9, on the rangefinder Nippon no.14. No.70067 is pictured in HPR, p.260, on the viewfinder Nippon no.1.810010.
  8. ↑ Lens reported and pictured in Mori, pp.94 and 100–1, pictured and sketched in Shirai, pp.17–8 and 20 (on the rangefinder Nippon no.23001).
  9. ↑ Lens pictured in HPR, pp.263–4, on the Nicca Peerless Type-3 no.24001.

Bibliography

  • Hagiya Takeshi (萩谷剛). "Raika to sekai no Raika-yō renzu" (ライカと世界のライカ用レンズ, Leica and other Leica-mount lenses). In Sekai no Raika renzu (世界のライカレンズ, Leica lenses of the world) Part 1. Tokyo: Shashinkogyo Syuppan-sha, 2003. ISBN 4-87956-061-8. Pp.178–88.
  • HPR. Leica Copies. London: Classic Collection Publications, 1994. ISBN 1-874485-05-4. Pp.258–60, 263–4 and 413.
  • Inoue, Mitsuo (井上光朗). "Shashin renzu no yoake. Renzu-ya Funsenki" (写真レンズの夜明け・レンズ屋奮戦記, Dawn of the photographic lens – Fierce war tales between lens shops). 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.14, October 1989. No ISBN number. Rikō kamera no subete (リコーカメラのすべて, special issue on Ricoh). Pp.128–132. (Contains a reproduction of an advertisement listing the K.O.L. Xebec, same as in Hagiya's article, and information on the Gojō company.)
  • "Kokusan shashinki no genjōchōsa" (国産写真機ノ現状調査, Inquiry into Japanese cameras), listing Japanese camera production as of April 1943. Reproduced in Supuringu kamera de ikou: Zen 69 kishu no shōkai to tsukaikata (スプリングカメラでいこう: 全69機種の紹介と使い方, Let's try spring cameras: Presentation and use of 69 machines). Tokyo: Shashinkogyo Syuppan-sha, 2004. ISBN 4-87956-072-3. Pp.180–7. Lens item Ja1.
  • Mori Ryōsuke (森亮資). "Sensō ga unda raika kopī-ki 'Nippon'" (戦争が生んだライカ・コピー機「ニッポン(Nippon)」, The 'Nippon' Leica copy, created by the war). 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.58, March 2001. ISBN 4-257-13032-6. Tokushū: Raika bukku '01 Raika kenkyū (特集:ライカブック'01・ライカ研究, Leica book '01: Leica research). Pp.94–103.
  • Shirai Tatsuo (白井達男). "Nippon Camera" (ニッポンカメラ). Pp.17–26 of Maboroshi no kamera o otte (幻のカメラを追って, Pursuing phantom cameras). Gendai Kamera Shinsho (現代カメラ新書). Tokyo: Asahi Sonorama, 1982. ISBN 4-257-08077-9. (First published in Kamera Rebyū / Camera Review. no.2, February 1978.)

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