Komura 100mm f/2 (Bronica)
Sankyo Koki · Bronica S · 1967
single source, unconfirmedAlso known as: Komura 100mm f/2 Bronica · Komura 100mm F2 for Bronica · Auto-Komura 100mm f/2 · Auto Komura 100mm F2 Bronica · Sankyo Koki Komura 100mm f/2 · Sankyo Kohki Komura 100mm F2 Bronica · KOMURA 100mm F2 For BRONICA · コムラー 100mm F2 ブロニカ · 三協光機 コムラー 100mm F2
Variants & identification
| Variant | Mount | Years | Serial ranges | Production |
|---|---|---|---|---|
| Auto-Komura 100mm f/2 for Bronica (pictured 1967) | Bronica S | — | — | — |
- No specification has been published. Japanese Wikipedia's Komura table lists the 100mm F2 with its construction, diaphragm and filter columns empty, and no other source adds a figure, so elements, groups, filter size, weight and minimum focus are all left blank.
- Date: 1967 is the earliest dated evidence, the Modern Photography article of November 1967 that Monaghan summarises, not a launch date. Seiden's history on Monaghan's page dates the Komura line as a whole to 1965–66 but does not include the 100mm f/2 in its list, so the lens may have come later than the first Komuras or simply have been left out.
- Diaphragm: 'Auto-Komura' is Monaghan's listing name, which implies an automatic diaphragm and hence the small bayonet; Japanese Wikipedia leaves the diaphragm column empty for this lens, and no owner's description has been found to confirm it.
- The Modern Photography piece, as summarised by Monaghan, remarked that the Rollei SL66's mirror blocked such fast lenses from reaching infinity while the Bronica's falling mirror did not, and that Komura's focusing mounts could be used to fit other lenses to Bronicas.
How to tell them apart
- A Komura engraved 100mm 1:2 with a Bronica mount; the common Komura 100 for the Bronica is the f/2.8, and the Zenzanon 100mm f/2.8 is Bronica's own lens of the length
- Nothing more can be said from published sources: no photograph of the lens on its own, filter size or barrel description has been found
Auto-Komura 100mm f/2 for Bronica (pictured 1967):
- Engraved 1:2 at 100 mm, a full stop faster than the Komura 100mm f/2.8 for the same mount; Monaghan's list calls it the 'Auto-Komura', so an automatic diaphragm on the small bayonet is to be expected
- Auto-Komura 100mm f/2 for Bronica (pictured 1967): Known only from mentions: Modern Photography of November 1967 pictured a Bronica with the 100mm f/2 Komura mounted and called it a speed lens for 6×6, Monaghan's consolidated list carries it as the Auto-Komura 100mm f2, Japanese Wikipedia lists it without figures, and shiura.com notes that a 100mm F2 existed in the Komura line for Bronica. No photograph of the lens itself, no specification and no price have been found.
Specifications
- Aperture range
- f/2
- Country
- Japan
What reviewers say
No reviews aggregated yet — this family is still in the research queue. Written one? We'd love to index it.
History
The Komura 100mm f/2 is the fastest lens recorded for the focal-plane Bronica apart from the Zenzanon 80mm f/2.4, and one of the least documented. It is known from three mentions: Simon Nathan’s “Simon Says” column in Modern Photography of November 1967, which pictured a Bronica with the 100mm f/2 Komura mounted and called it one of a number of speed lenses developed for 6×6, a lens whose deep rear the Rollei SL66’s mirror would have blocked but the Bronica’s falling mirror cleared; Monaghan’s consolidated list, which carries it as the Auto-Komura 100mm f2 on the strength of that article; and the Japanese sources, Japanese Wikipedia’s Komura table and Shinsaku Hiura’s lens page, which list it by name and nothing else.
No specification has been found. Japanese Wikipedia gives construction, diaphragm and filter figures for the 45, 50, 100mm f/2.8, 150 and 200 mm Komuras and leaves the columns empty for this lens, and no photograph of the lens on its own, no price and no owner’s description has turned up. Monaghan’s “Auto-Komura” implies an automatic diaphragm and so the small bayonet at the front of the Bronica helicoid, which is where every lens from 40 to 200 mm sits, but that is an inference from a listing name. The 1967 of the article is the earliest dated evidence rather than a launch date: Seiden’s history puts the Komura line at 1965–66, but its list of the lenses does not include the 100mm f/2.
Anyone who meets one should record what the published sources lack: the engraving, the filter size, the diaphragm coupling and the serial number. Until then the lens stands in the catalogue as an attested name, with the Komura 100mm f/2.8 as the lens a seller offering a “Komura 100” for Bronica is far more likely to have.
This history is AI-written, from the sources listed at the foot of the page. Where the record is silent it says so rather than filling the gap — but no human wrote these sentences.
Example photos
Sample photo wanted — shot with a Komura 100mm f/2 (Bronica)? We'd love to feature it (with credit).
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