KMZ Jupiter-11 135mm f/4 (Contax RF)

KMZ Jupiter-11 135mm f/4 (Contax RF)

The KMZ Jupiter-11 135mm f/4 is a coupled telephoto lens for the Contax/Kiev external bayonet. It uses an independent focusing helicoid and a four-element, three-group Sonnar-derived optical construction.

The twelve-blade iris is continuously adjustable from f/4 to f/22. Most Contax/Kiev examples focus to approximately 1.5 metres. This materially distinguishes the barrel from the longer M39 rangefinder version, which commonly focuses only to 2.5 metres.

Optical qualities

Rendering

At full aperture the Jupiter-11 produces good central detail with moderate contrast and gentle transitions into defocus. Residual spherical aberration can give highlights and fine detail a softer appearance at f/4.

Stopping down to f/5.6 or f/8 increases contrast and improves definition across the frame. The twelve-blade aperture helps retain rounded out-of-focus highlights.

History

Development and Launch

The Jupiter-11 developed from the wartime and immediate post-war Zeiss Sonnar 135mm design lineage. Regular Jupiter-branded production began around 1950.

Production Evolution

KMZ produced early versions, followed by production at KOMZ and other Soviet facilities. Factory and engraving changes do not require separate optical profiles.

Special Editions and Variants

Some early Kiev-bayonet barrels are reported with a 2.5-metre focusing scale. These should be described as a production variation, not merged with the mechanically different M39 profile.

Collector Notes

Check the long helicoid for stiffness, verify rangefinder calibration and inspect the numerous aperture blades for oil or deformation.