Japanese medium-format SLR (edit)
6×9 Rittreck (6×9)
6×8 Fujifilm GX680
Japanese TLR and pseudo TLR ->
Other Japanese 6×6, 4.5×6, 3×4 and 4×4 ->

The Konica SF (コニカSF) is a 4.5×6 SLR camera made as a prototype by Konishiroku in the second half of the 1960s.

Development and fate[]

Konishiroku's medium-format SLR project started in June 1965.[1] (Actually, the company had already built an unrelated 6×6cm SLR prototype in the 1940s or early 1950s, but almost nothing is known on that camera, see Konishiroku 6×6 SLR.) The main objectives were a good image quality, an advanced exposure system, the ability to take snapshots, and a price as low as possible.[1] The potential customers were mainly professional studio or scientific photographers and high-end amateurs, but the camera would have to be usable for press photography too.[1] The main designer for the project was Nenoi Masayuki (根ノ井正之), who also designed the Konica Auto S and Konica Domirex.[2]

The Konica SF was announced in Japanese photography magazines, but the exact date is unclear — either Spring 1967 or Spring 1968.[3] However, the camera never went into full production. One cause for this was Nenoi's unexpected death.[4] In addition to that, Konica officials interviewed in the late 1970s explained that the company did not want to disperse its efforts on too many projects.[5]

The Konica SF was the first Japanese 4.5×6 SLR, years before the Mamiya M645, and one of the first medium-format SLRs in the world to have automatic exposure. In 1968, Minolta made a prototype SLR in 6×6cm format, the Minolta SR66, having an electronically controlled shutter, perhaps enabling auto-exposure too, but that project was also shelved.


The Konica SF has exchangeable film backs for 15 frames on 120 or 30 frames on 220 film, a metal focal-plane shutter by Copal (1–1000, B),[6] and through-the-lens metering for shutter-priority automatic exposure. The design allows for interchangeable lenses and finders, and the lens mount is compatible with Hasselblad. The lenses made for the Hasselblad can be mounted on the Konica SF but can be used in manual exposure mode only.[7] The dedicated SF lenses have an additional pin for auto-exposure operation, and they cannot be mounted on the Hasselblad.[7] The film advance knob is interchangeable too and can be replaced by an advance crank; this would have allowed the future development of a motor-drive.[7]

Two prototypes were made,[7] and at least one of them has survived. It has been photographed and exhibited with a pentaprism finder and a Hexanon 80mm f/2.8 standard lens (no.4610002), and was notably displayed at the JCII exhibition about Konica and Minolta in 2005.

The 80mm f/2.8 lens has seven elements in five groups,[8] and focuses down to 0.6m.[1] Prototypes of a wide-angle 50mm f/3.5 and a tele 135mm f/3.5 were made, and at least one example of each has survived.[9] Both are called Hexanon too; the minimum distance is 0.5m for the 50mm, and 1.2m for the 135mm.[1] The three lenses are predominantly black, and share the same aspect. The focus ring has a diamond-shaped pattern and is graduated in both metres and feet. There is a chrome band under the focus ring, with depth-of-field indications. The aperture ring is close to the lens mount, and has an additional position beyond f/22 for automatic exposure.

Other lenses were planned but never made: 35/4, 180/4.5, 250/5.6 and 500/8.[10] (Intended minimum focusing distances were respectively 0.5m, 2m, 2.5m and 8m.)[11]


  1. 1.0 1.1 1.2 1.3 1.4 Shirai, p.81.
  2. Shirai, pp.80–1.
  3. Shirai, p.78, says that the Konica SF was announced in Spring 1967, at the same time as the Koni-Omegaflex M, but the latter camera is dated 1968 in many other sources. Hishida, p.81 of Kurashikku Kamera Senka no.10, says 1967 too, but the text is obviously based on Shirai. Lewis, p.125, says March 1968 for both the Konica SF and Koni-Omegaflex M.
  4. Shirai, pp.81 and 86, repeated in Hishida, p.81 of Kurashikku Kamera Senka no.10.
  5. Shirai, p.86, repeated in Hishida, p.81 of Kurashikku Kamera Senka no.10.
  6. Shutter by Copal: Lewis, p.125, and Hishida, p.81 of Kurashikku Kamera Senka no.10.
  7. 7.0 7.1 7.2 7.3 Hishida, p.81 of Kurashikku Kamera Senka no.10.
  8. Shirai, p.77.
  9. Pictures in Shirai, p.85, and in Hishida, p.81 of Kurashikku Kamera Senka no.10.
  10. Shirai, p.82, repeated in Hishida, p.81 of Kurashikku Kamera Senka no.10.
  11. Shirai, p.82.