Carl Zeiss Sonnar 135mm f/4

Carl Zeiss Sonnar 135mm f/4

The Carl Zeiss Sonnar 135mm f/4 is the post-war West German generation of the classic Contax rangefinder telephoto. Introduced in 1950, it retains a compact four-element, three-group Sonnar construction but belongs to a separate Oberkochen production line from the earlier Carl Zeiss Jena lens.

The lens uses the Contax external bayonet and incorporates its own focusing helicoid. It couples to the camera rangefinder and focuses down to approximately 1.5 metres. The factory specified an angle of view of approximately 18 degrees.

Its twelve-blade diaphragm maintains a comparatively rounded aperture as the lens is stopped down. A 40.5mm filter fitting matches several other lenses in the post-war Contax system.

Optical qualities

Rendering

The 135mm Sonnar combines compressed perspective with a narrow field of view and strong subject isolation. The four-element construction produces clear central definition while retaining gradual transitions into out-of-focus areas.

Sharpness

Central sharpness is strong at f/4. Stopping down to f/5.6 or f/8 increases contrast and improves consistency across the frame. Accurate rangefinder calibration remains important because the narrow angle of view magnifies small focusing errors.

Bokeh

The long focal length and twelve-blade diaphragm produce smooth background separation, especially at portrait distances. Out-of-focus highlights remain relatively rounded across much of the aperture range.

Contrast and flare

All West German examples were coated, including lenses without an explicit T marking. Coating and the small number of optical groups provide useful contrast, but strong frontal light can still create flare or reduce shadow density. A correct hood is recommended.

History

Development and Launch

Oberkochen introduced its post-war Contax 135mm Sonnar in 1950. Although it continued the established 4/3 Sonnar concept, contemporary references describe it as a West German recalculation rather than continued Jena production.

Production Evolution

Early lenses carry Zeiss-Opton markings and usually display the red T coating symbol. From 1953, the front-ring inscription changed to Carl Zeiss and the T symbol was normally omitted because coating had become standard.

The Zeiss-Opton and Carl Zeiss markings represent successive stages of the same West German optical and mechanical generation and are covered by this profile.

Special Editions and Variants

Minor engraving, scale and coating-symbol differences are known. These should not be merged with the pre-war Carl Zeiss Jena 135mm f/4 or later Contarex and SLR lenses carrying the Sonnar name.

Collector Notes

Check the long focusing helicoid for even movement and confirm rangefinder accuracy at both medium distance and infinity. Internal haze, separation, cleaning marks and coating damage can materially reduce contrast. Original caps, hood, finder and case are useful additions to a complete Contax outfit.