Sankyo-Kohki W-Komura 35mm f/2.8

Sankyo-Kohki W-Komura 35mm f/2.8

The W-Komura 35mm f/2.8 is one of the wide-angle screw-mount lenses produced under the Komura brand by Sankyo-Kohki, a Japanese maker that supplied optics for a wide range of camera systems rather than building its own camera bodies [1]. In Leica thread mount (LTM/M39) it is far less commonly encountered than the firm's longer telephoto offerings, and surviving examples in clean condition tend to draw interest from collectors of Japanese rangefinder glass. The "W" prefix denotes its wide-angle role within the Komura lineup, alongside other wide focal lengths such as the W-Komura 24mm and 28mm [1].

Optically the lens uses a six-element design arranged in four groups, with an eight-blade diaphragm and a closest focusing distance of about one metre. It is a genuinely compact unit, roughly 29 mm long and around 170 g, taking 43 mm filters. In its LTM form it is rangefinder-coupled, so focus is set through the camera's coupled rangefinder rather than by scale alone. Aperture is controlled by a ring on the barrel; users coming from Japanese rangefinder lenses of the period have noted that the Komura aperture scale can rotate in the opposite direction to some rival lenses, which is a handling quirk rather than a fault [2]. Build quality is solid and conventional for an all-metal lens of its era.

The same optical block was offered in several rangefinder mounts, including Nikon S bayonet, where the f/2.8 version is regarded as the scarcer variant of the Komura 35mm line [2]. Because Sankyo-Kohki marked its products variously as Sankyo Koki, Sankyo Kohki and later Komura Lens, barrel engravings can differ between examples, and mount type should be confirmed visually before purchase since the brand made lenses for many systems [1].

Optical qualities

Rendering Documentation specific to this lens is limited, and most published observations come from users of the optically equivalent rangefinder versions. The overall character is described as distinctly vintage rather than clinical [2].

Contrast and color On black-and-white film the lens is reported to give pleasing contrast, while color results are described as acceptable but not strictly neutral, with somewhat exaggerated hues [2].

Flare resistance The lens is said to control flare well in most situations, but can produce a strong, unusual flare pattern when shooting into bright light [2].

Distortion and vignetting One user account notes little vignetting wide open, with some darkening of the corners appearing as the lens is stopped down, the reverse of the more usual behaviour [2]. These remarks reflect individual experience rather than measured testing.

History

Development and Launch Sankyo-Kohki traces its origins to an optical research operation established in Japan in 1951, reorganised as Sankyo Kohki Co., Ltd. in 1955 [1]. The Komura brand name was coined from the names of senior figures in the company when it settled on a trademark [1]. The firm built a catalogue of interchangeable lenses across rangefinder and SLR mounts, including Leica screw mount, within which the W-Komura wide-angles sit [1].

Production Evolution The company changed its name to Komura Lens Mfg. Ltd. in 1969 and continued producing lenses, including an interchangeable-mount system, before ceasing operations around 1980 [1]. Across this span the same wide-angle optics were offered in multiple mounts, which accounts for the variation in mount and engraving seen on surviving lenses [1].

Special editions No major factory special editions of the W-Komura 35mm f/2.8 in LTM are widely documented. The principal variation of note is the availability of the same optical design in other rangefinder mounts such as Nikon S, with the f/2.8 considered the less common version of the Komura 35mm family [2].

Collector Notes Because Sankyo-Kohki marked lenses under several closely related names, buyers should confirm the actual mount and read the engravings carefully rather than relying on a listing title [1]. Examples are not abundant, and matching accessories such as the original auxiliary finder add to desirability for the rangefinder versions [2]. As with many lenses of this age and origin, the condition of the glass and coatings is worth checking carefully before purchase.

Sources

• [1] Kameramanufaktur. Sankyo Kohki and the Komura lenses. https://kameramanufaktur.jimdofree.com/lenses/komura-lenses/
• [2] 35mmc. Komura 35mm f/2.8 in Nikon S mount - a Hidden Gem. https://www.35mmc.com/18/08/2023/komura-35mm-f-2-8-in-nikon-s-mount-a-hidden-gem/