Kowa Prominar 35mm f/2.8

Kowa Prominar 35mm f/2.8

The Kowa Prominar 35mm f/2.8 is a rare Japanese wide-angle lens made by Kowa Optical Works for Leica screw-mount rangefinder cameras. Its compact metal barrel, coupled focusing and small reported production run distinguish it from the fixed-lens Prominars fitted to Kowa cameras.

Optical Qualities

The lens uses six elements in four groups. The 35mm focal length provides a moderately wide field of view on 35mm film, while the f/2.8 maximum aperture keeps the lens relatively compact. Results from surviving examples can vary with coating, haze and optical condition.

History

Lens reference catalogues date the model to 1957. OstLicht auction documentation describes production around 1959 and reports that approximately 100 examples were made. It belongs to the small group of independent Japanese Leica thread-mount lenses produced during the rapid growth of Japan's post-war camera industry.

Handling

The lens focuses to approximately 3.5 feet, or 1.07 metres, and accepts 34mm filters. Its original focusing mechanism is mechanically coupled to the camera rangefinder. A separate 35mm finder may be useful on screw-mount camera bodies without matching framelines.

Compatibility

Original examples use the Leica thread mount, also known as LTM or M39, and include rangefinder coupling. They can be mounted directly on compatible screw-mount cameras and used on Leica M bodies with a suitable LTM-to-M adapter.

Sources

• OstLicht Auction, Kowa Optical Works M39 Prominar 2.8/35mm
• The Lens DB, Kowa Prominar 35mm f/2.8 LSM