KMZ Russar MR-2 20mm f/5.6 (Contax RF)

KMZ Russar MR-2 20mm f/5.6 (Contax RF)

The KMZ Russar MR-2 20mm f/5.6 (Contax RF) is an exceptionally rare Kiev adaptation of the Soviet Russar ultra-wide lens. KMZ supplied the 20mm optical module, while Arsenal produced the special adapter for the Contax/Kiev inner bayonet.

The adapter engages the focusing helicoid inside the camera body. Unlike an ordinary coupled 50mm inner-bayonet lens, however, the Russar adaptation does not provide usable rangefinder coupling. Focusing must therefore be performed from the engraved distance scale and the lens's extensive depth of field.

Documentation shows two prototype configurations. One adapter lacks a distance scale, while another carries its own focusing scale. Both are distinct from the standard M39 Russar, which has an integrated focusing mount. Exact dimensions, weight and focusing limit of the complete adapted assembly have not been documented consistently, so those fields remain Unknown.

The lens retains the six-element, four-group Russar optical module, seven-blade diaphragm and 49mm front accessory thread of the original KMZ lens. It is intended for Contax/Kiev bodies retaining the conventional inner-bayonet lock. It is not suitable for the Kiev-5, which lacks that inner-bayonet locking arrangement.

Optical qualities

Rendering

The symmetrical 20mm Russar construction produces an exceptionally wide field of view in a very compact optical package. The moderate f/5.6 maximum aperture and short focal length provide extensive depth of field, making scale focusing practical despite the absence of usable rangefinder coupling.

Sharpness

Period specifications describe good central and mid-field resolution. Edge performance is more dependent on aperture, optical alignment and the condition of the strongly projecting rear element.

Contrast and flare

The original lens uses single-layer coating. Clean examples can deliver good contrast, but direct light may cause flare and veiling. Haze, coating damage and internal contamination have a substantial effect on surviving examples.

Distortion and vignetting

The Russar scheme was developed to provide a very wide rectilinear field while controlling distortion and illumination loss more effectively than many earlier symmetrical wide-angle designs.

History

Development and Launch

The Russar optical scheme was developed by Soviet optical designer Mikhail Mikhailovich Rusinov. GOI completed the prototype lens during the 1950s, and the commercial M39 version entered KMZ production shortly before its international recognition at the 1958 Brussels exhibition.

Production Evolution

The normal Russar MR-2 was manufactured as an M39 scale-focus lens. The Contax/Kiev version was not a conventional production mount variant. It combined a KMZ optical module with an Arsenal-made inner-bayonet adapter.

Special Editions and Variants

Two prototype adapter forms are documented: one without a distance scale and one with a dedicated scale. No regular production series or confirmed factory catalogue number for the complete adaptation has been established.

Collector Notes

A genuine example should be distinguished from later private conversions. The Arsenal adapter, its engagement with the camera helicoid and the absence of usable rangefinder coupling are the defining mechanical features. Rear-element condition and the authenticity of the adapter are particularly important.