Sankyo Kohki

Sankyo Kohki (later Komura Lens Mfg. Ltd.) was a prolific Japanese optical manufacturer that peaked during the 1950s and 60s. For the Leica M-mount and LTM community, the brand is best known for its Komura line of lenses. These optics occupy a unique niche: they were among the first affordable, high speed third party options available for rangefinder users, offering specifications (like f/1.8 portrait lenses or f/2 telephotos) that were often faster or cheaper than their Leitz or Nikon equivalents.

While often dismissed in the past as a "budget" brand, Komura lenses have recently gained a cult following. Collectors now hunt for them due to their unique optical recipes (often based on the Ernostar rather than the Sonnar or Planar), which produce a distinctively vintage, painterly bokeh that modern lenses cannot replicate.

History

Sankyo Kohki's story is one of ambitious engineering that eventually succumbed to the dominance of major camera brands.

The Chibanon Roots (1950s)

The company began operation in Tokyo in the early 1950s, originally producing lenses under the name Chibanon (often found on enlargers or obscure cameras). By 1953, they established the Komura trademark, which became their primary identity for interchangeable lenses.

The Rangefinder Golden Age (1955 to 1960s)

Unlike other third party manufacturers that focused on simple 35mm and 135mm lenses, Sankyo Kohki was aggressive. They produced a massive array of LTM lenses ranging from 28mm to 200mm. They were particularly famous for their fast telephotos, filling a gap for photographers who wanted speed without paying Leica prices.

• The "Unidapter" Era: In their later years (post 1960s), Komura shifted focus to SLRs and medium format (Bronica), developing a "Unidapter" system that allowed one lens head to be used on multiple mounts. However, their earlier native LTM lenses are the ones prized by rangefinder users today [[1]].

Product Lines (LTM Native)

Komura LTM lenses are generally characterized by solid all metal construction (black and chrome) and impressive aperture speeds for their era.

The "Ernostar" Telephotos

This is where Sankyo Kohki truly shines. Instead of copying the Zeiss Sonnar, many of their fast telephotos utilized Ernostar derived designs, known for high center sharpness but rapid fall off toward the edges.

• Komura 105mm f/2 & f/2.5: The 105mm f/2 is the brand's "unicorn." It is a massive, heavy lens that offers a unique, swirling bokeh and razor thin depth of field. It is often compared to the legendary Nikkor 10.5cm f/2.5 but with a "wilder" character [[2]].
• Komura 80mm f/1.8: A rare, super fast portrait lens. At a time when Leitz only offered the 75mm Summilux (which came decades later) or slow 90mm lenses, this provided a unique high speed option for low light stage and portrait work.

The W-Komura (Wide Angle)

• W-Komura 35mm f/2.8: The workhorse of the lineup.
  • Design: A competent 6 or 7 element retrofocus design that is surprisingly sharp stopped down.
  • Build: Early versions are heavy brass with chrome finish; later versions are lighter alloy with black/chrome styling. They often feature distinct "click" stops that are louder and more mechanical than Leica lenses [[3]].
• W-Komura 28mm f/3.5: A compact wide angle that is often overlooked. It is known for decent sharpness but lower contrast, making it excellent for black and white photography.

The Super-Telephotos

• Komura 200mm f/4.5: One of the few rangefinder coupled 200mm lenses in existence. While practical framing is difficult (Leica viewfinders don't go beyond 135mm), it remains a technical curiosity for collectors who want to push the rangefinder mechanism to its absolute limit.

Why Photographers Choose Sankyo Kohki

• The "Portrait" Look: The 105mm f/2 offers a rendering that is distinct from the clinical sharpness of modern lenses. It provides a soft, flattering glow for skin tones while obliterating the background, making it a cheaper alternative to the Summarex.
• Speed on a Budget: For users who want to experiment with f/1.8 or f/2 telephotos on a Leica, Komura remains one of the most accessible entry points compared to the skyrocketing prices of Nikkor or Canon LTM glass.
• Historical Curiosity: The sheer ambition of producing a coupled 200mm lens or a fast 80mm prime demonstrates a "can do" engineering spirit that appeals to collectors of eccentric Japanese optics.

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Sources

• [1] Camerapedia (Sankyo Kohki History): https://camerapedia.fandom.com/wiki/Sanky%C5%8D_K%C5%8Dki
• [2] Johan Niels (Komura LTM Overview): https://johanniels.com/komura-lenses-for-leica-cameras-overview/
• [3] 35mmc (W-Komura 35mm Review): https://www.35mmc.com
• [4] Pentax Forums (Komura Lens Reliability): https://www.pentaxforums.com/userreviews/sankyo-kohki-komura-135mm-f2-8.html