4995251185 413f889fa3 m

K.O.L. Special 75mm f/3.5 on a Mamiya Six I

36891955365 3bc0be0aa0 m

K.O.L. Sola Special 75mm f/3.5 on a Mamiya Six III.

48710747581 810a0a4673 m

Kadera Anastigmat 75mm f/4.5 lens on a Semi Kinka

Kajiro Kōgaku Kenkyūjo (上代光学研究所, Kajiro Optical Laboratory) was a Japanese optical company. It was founded in July 1939 by Kajiro Hitoshi (上代斉), who previously worked for Miyoshi Kōgaku. The initials K.O.L. (for Kajiro Optical Laboratory) were adopted as the brand name of the lenses. K.O.L. is engraved in the lenses in handwritten style.

The company became Gojō Kōki Seisakusho (五城光機製作所) in 1941, apparently building a new plant. It is said that the old plant and brand names were transfered to Kokusaku Seikō, a camera maker which was already buying lenses for its Auto Keef model. However the relation between the two companies is not yet clearly understood: advertisements mention the two company names "K.O.L. Gojō Kōki Seisakusho" and "Kokusaku Seikō K.K." together, and the April 1943 government inquiry on camera production attributes the K.O.L. lenses to Gojō (五城), Kokusaku (国策) or Tōa Kokusaku (abbreviated 東亜国) with no apparent logic. The address of K.O.L. Gojō in 1944 was Yodobashi Shimo-ochiai 2–969 in Tokyo (東京・淀橋・下落合二ノ九六九), very close to that of Kokusaku.

Activity stopped in 1945, but some time after the company Gojō Kōki was revived as Sun Kōki.


K.O.L. range[]

An advertisement for the K.O.L. lenses, mentioning both Gojō and Kokusaku, lists the following lenses:

  • K.O.L. Anastigmat f/4.5, 75mm;
  • K.O.L. Anastigmat f/3.5, 60mm and 75mm;
  • K.O.L. Sola f/3.5, 50mm and 75mm, four elements;
  • K.O.L. Gōka f/2.8, 60mm, 75mm and 80mm, four elements;
  • K.O.L. Xebec f/2, 50mm, six elements.

The K.O.L. Xebec is a collapsible lens in Leica screw mount, and has six elements in four groups. It is said that a 50mm f/1.5 lens with seven elements in five groups was developed in 1943, but it was only used for X-ray photography.

Other K.O.L. lens names are as follows:

  • K.O.L. Elmo 75mm f/3.5 (three elements)
  • K.O.L. Keef 60mm f/3.5 (three elements), on the Auto Keef
  • K.O.L. Nōman Trio 75mm f/3.5 (three elements), on the Nōman Flex
  • K.O.L. Special 75mm f/3.5 (three elements), on the Mamiya Six, models I and II
  • K.O.L. Trio 75mm f/3.5 (three elements)
  • K.O.L. Taro Anastigmat 7.5cm f/3.5, on the Taroflex



  • U Hitonar 75mm f/3.5 (three elements), by Kokusaku, on the Rollekonter
  • Kadera 75mm f/3.5 (three elements), by Gojō, on the Semi Kinka


  • Hitonar 75mm f/3.5 and f/4.5, on the Rollekonter, Semi Ace and Semi Miss
  • U Hitonar 75mm f/4.5, on the Semi Konter
  • Kadera 75mm f/4.5, on the Kadera and Semi Kinka

Cameras equipped[]

The following list is incomplete. That a particular model is listed should not be taken to mean that all examples were fitted with lenses made by Kajiro, Gojō or Kokusaku.

  • Elmoflex
  • Gaica II (K.O.L. Gaica)
  • Auto Keef (K.O.L. Keef 60/3.5)
  • Kadera (Kadera 75/4.5)
  • Semi Kinka (Kadera 75/3.5 and 75/4.5)
  • Semi Konter (Hitonar 75/3.5 and 75/4.5, U Hitonar 75/4.5)
  • Semi Kreis (K.O.L. Special and K.O.L. Trio)
  • Semi Kreis II and III (K.O.L. Trio)
  • Lark (K.O.L. Trio)
  • Mamiya Six (K.O.L. Trio, then K.O.L. Special, then K.O.L. Sola)
  • Semi Miss (Hitonar 75/3.5 and 75/4.5)
  • Nōman Flex (K.O.L. Nōman Trio or perhaps K.O.L. Nōman Trion)
  • Rollekonter (Hitonar 75/3.5 and 75/4.5, U Hitonar 75/3.5)
  • Semi Rosen III (Keef 75/4.5)
  • Taroflex (K.O.L. Taro Anastigmat)
  • Weha Chrome Six III New (K.O.L. Gojo, one example reported only)

References/External Links[]

All credit goes back to Camera Wiki Org for i do not own any of these information nor the pictures provided in this page