The Carl Zeiss Opton Sonnar 50mm f/2 is a coated postwar West German Contax rangefinder lens, a collectible six-element Bertele Sonnar design.</parameter> <parameter name="long_description">## Carl Zeiss Opton Sonnar 50mm f/2 The Opton Sonnar 50mm f/2 represents the West German continuation of one of the most influential rangefinder lens designs of the twentieth century. It is the slower, more affordable sibling of the famous f/1.5 Sonnar, built on the same optical principle conceived by Ludwig Bertele, who developed the fast Ernostar at Ernemann before that firm was absorbed into Zeiss [1]. The "Opton" marking on the barrel identifies it as a product of the Oberkochen branch of Carl Zeiss after the company was split between East and West Germany following the Second World War, when the western operation relaunched the lens as Zeiss-Opton around 1950. Optically the lens follows the classic Sonnar layout of six elements arranged in three groups, comprising one single element and two cemented groups. This compact three-group structure was central to Bertele's achievement, since reducing the number of air-to-glass surfaces lowered internal reflections and flare in an era before anti-reflective coatings, while still delivering high effective speed. The Opton-era lenses carried the red T anti-reflective coating, a meaningful improvement over the uncoated prewar Sonnars, and the body was built from chrome over brass. It is a compact, all-metal lens for the Contax rangefinder bayonet mount; on these cameras focus is driven through the camera body's helicoid rather than a coupling mechanism on the lens barrel itself, and the lens is finished in silver chrome with an eleven-blade iris. The Opton name is itself a useful identification marker. The branding existed because of the postwar dispute over the Carl Zeiss trademark, and the marking changed as the situation evolved. The final type of these lenses, built around 1953, was no longer marked Zeiss-Opton once Zeiss Ikon regained the rights to use the "Carl Zeiss" brand; that later type also dropped the aperture-ring grips and stopped down to f/16. Earlier in the run, a black filter ring was introduced from 1951, and around 1952 a version that stopped down to f/22 appeared. Because the f/2 Sonnar was produced in both prewar Carl Zeiss Jena form and postwar East and West German forms, the Opton marking together with the coating and chrome-over-brass construction is one of the clearest ways to place a given example in the West German postwar production. --- ## Optical qualities **Rendering** The postwar Opton Sonnar f/2 inherits the rendering reputation of the Sonnar family, which is rooted in its low-flare, high-contrast three-group design and, in this generation, the addition of T coating. Detailed, independently measured optical data for this specific f/2 variant is limited in the sources consulted, so claims about its sharpness, bokeh, and aberration behavior should be treated cautiously. What can be said with confidence is that the coating was a real advance over the uncoated prewar Sonnars in reducing reflections and light loss, which generally improves contrast. --- ## History **Development and Launch** The Sonnar name derives from the German word Sonne, meaning sun, and the modern Sonnar was introduced by Carl Zeiss Jena in 1932 for the Contax rangefinder system as a complete redesign that abandoned the earlier Tessar-derived lens of that name in favor of a layout based on the Ernostar. At its introduction the Contax Sonnar was the fastest lens available at f/1.5, and a slower f/2 budget version was offered alongside it. The f/2 Sonnar therefore existed from the line's earliest days as the more economical normal lens for Contax users. **Production Evolution** After the war Zeiss was divided between East and West Germany, and the western branch in Oberkochen relaunched the lens as Zeiss-Opton around 1950 with a new optical design and red T coating, in a chrome-over-brass body. A black filter ring followed from 1951, and around 1952 apertures extending to f/22 were introduced. The final lenses of 1953 abandoned the Zeiss-Opton marking in favor of "Carl Zeiss," dropped the aperture-ring grips, and stopped down to f/16. **Special editions** No major factory special editions of the postwar Opton f/2 Sonnar are widely documented in the sources consulted; the notable variation within the line concerns the marking, coating, minimum aperture, and filter-ring changes described above rather than distinct commemorative or military versions. **Collector Notes** For buyers, the most useful identification points are the "Zeiss-Opton" marking with the red T, which together signal a postwar West German example rather than a prewar Carl Zeiss Jena lens or an East German postwar build. The presence or absence of the aperture-ring grips and the marked minimum aperture (f/16 versus f/22) help narrow the production period. As with all coated Sonnars of this age, the soft early coatings and the cemented groups make haze and coating condition worth inspecting closely before purchase. Note also that the same f/2 Sonnar design lived on in Soviet form as the ZK and then the Jupiter-3 after the USSR moved Zeiss tooling to Kiev, so the design lineage is easily confused with later copies even though those are differently marked and constructed. --- ## Sources * [1] Camera-wiki.org. *Sonnar 50mm*. https://camera-wiki.org/wiki/Sonnar_50mm * [2] Kamerastore. *Carl Zeiss 50mm f2 Sonnar T* Opton - Lens*. https://kamerastore.com/en-us/products/carl-zeiss-50mm-f2-sonnar-t-opton-contax-kiev * [3] LENS-DB.COM. *Carl Zeiss / Zeiss-Opton Sonnar 50mm F/2*. https://lens-db.com/zeiss-opton-carl-zeiss-contax-sonnar-50mm-f2

Carl Zeiss Opton Sonnar 50mm f/2

Contax RF mount