Sankyo-Kohki W-Komura 28mm f/3.5

Sankyo-Kohki W-Komura 28mm f/3.5

The W-Komura 28mm f/3.5 belongs to the wide-angle end of Sankyo Kohki's rangefinder lineup, the W prefix marking it as a wide-angle design. It sits among a family of Leica thread mount and Nikon rangefinder lenses that the company produced under the Komura brand during the era when Japanese makers were challenging the established German names on price and image quality [1][2]. By 1960 Sankyo Kohki had become one of the largest third-party lens makers in Japan, and its wide-angle and medium telephoto lenses were popular for offering competitive optical quality at lower cost than the better-known marques [1]. Within that range, the 28mm f/3.5 is the shortest rangefinder-coupled focal length documented in the Leica/Canon screw-mount lineup [2].

The lens uses a six-element design in four groups and a Leica thread mount (M39 / LTM), with rangefinder coupling so focus can be confirmed through a compatible body's coupled finder. The diaphragm runs on eight blades, the front accepts 55mm filters, and the barrel is compact at about 33mm long and around 170g, focusing down to one meter. As a manual lens it has no electronic contacts and no six-bit coding, and it is finished in black. On modern mirrorless cameras it can be adapted through a simple LTM-to-mount adapter, though as a wide rangefinder design the rear elements sit close to the film plane, which is worth bearing in mind on sensors.

Sankyo Kohki sold its rangefinder lenses under the Komura name across several mounts, with Leica thread mount and Nikon rangefinder versions being the most common [1][2]. The company's lenses were marketed on sharpness and value, and an American distribution presence followed a US trademark filing in late 1962 [1]. Detailed, lens-specific version histories for the 28mm f/3.5 are not well documented in accessible references, so claims about coating changes or barrel revisions should be treated with caution.

Optical qualities

Rendering Independent, lens-specific test data for the W-Komura 28mm f/3.5 is scarce, so its rendering is not well documented. In general terms it is a moderate-aperture wide-angle of late-1950s to 1960s Japanese design, and the maker's range as a whole was regarded as offering good image quality for the price [1]. Specific claims about its sharpness, contrast, flare behavior, distortion, or vignetting are not supported by reliable published testing, and are best assessed on a given sample rather than assumed.

History

Development and Launch Sankyo Kohki Co., Ltd. traced its origins to an optical research institute established in 1951 and was reorganized under the Sankyo Kohki name in 1955, adopting the Komura brand for its lenses [3]. The brand name was drawn from the names of the company's leadership [3]. Through the late 1950s and 1960s the firm built a broad catalogue of interchangeable lenses, and its rangefinder offerings in Leica thread and Nikon rangefinder mounts placed wide-angle options such as the 28mm f/3.5 alongside standard and telephoto Komura lenses [1][2].

Production Evolution By 1960 Sankyo Kohki had grown into one of Japan's largest third-party lens manufacturers, and exposure to Western photographers led to a US trademark filing for the Komura name in December 1962, after which the lenses were distributed in the United States [1]. A period catalogue listed around 40 lenses from 28mm to 800mm supporting most rangefinder, SLR, and C-mount cameras, with the 28mm to 200mm focal lengths supplied in direct, dedicated mounts [1][2]. The company was later renamed Komura Lens Manufacturing Ltd. around 1969 and went bankrupt in 1980 [3].

Special editions No major factory special editions of the W-Komura 28mm f/3.5 are widely documented. The lens was produced as a third-party rangefinder optic, and the Komura range as a whole appeared in numerous mounts rather than as distinct limited variants [1][2].

Collector Notes Komura rangefinder lenses are comparatively uncommon today and turn up most often through Japanese sellers [2]. Buyers should verify that a given example is the rangefinder-coupled Leica thread mount version rather than a fixed-mount or adapter-based variant, since the Komura name spanned many mounts [1][2]. As with most lenses of this age and origin, internal haze and coating condition are worth checking, and the maker's preset-aperture designs in particular were noted for rear elements prone to fogging, so glass should be inspected carefully [3]. One published reference lists a 48mm filter size for the 28mm f/3.5 rangefinder lens, which differs from the 55mm filter thread recorded here; published sources vary, so the filter ring should be measured on the actual lens before buying filters [2].

Sources

• [1] Mike Eckman. Sankyo Kohki Komura 500mm f/7. https://mikeeckman.com/2022/10/sankyo-kohki-komura-500mm-f-7/
• [2] Camerapedia. Sankyō Kōki. https://camerapedia.fandom.com/wiki/Sanky%C5%8D_K%C5%8Dki
• [3] Kameramanufaktur. Sankyo Kohki and the Komura lenses. https://kameramanufaktur.jimdofree.com/lenses/komura-lenses/