{"overview":"The Contax 21mm f\/4.5 Biogon is a wide-angle prime lens originating from the rangefinder era and made for the Contax rangefinder mount. Renowned for its symmetrical wide-angle design, it was conceived for landscape, architecture and reportage work where coverage and corner-to-corner rendering mattered.","market_narrative":"Auction data is thin: a single UK saleroom result from 2020 saw a copy hammer at £200, so that figure is the only firm reference point for what the lens sells for at wholesale level. With just one verified hammer price, today's market value should be treated as indicative rather than a true median, and clean, collectable examples in original mounts can attract premiums above this baseline. As of 2026, buyers asking what the 21mm Biogon is worth should weight condition, completeness and matching finder availability heavily when judging price.","buying_guide":"Inspect the front and rear elements carefully for fungus, haze and cleaning marks, as these older coatings are vulnerable and any haze on the rear group will degrade contrast noticeably. Check the aperture blades for oil migration, confirm the focus helicoid turns smoothly without grinding or stiffness, and look for any signs of element separation or coating scratches around the edges. Confirm the mount is correct for your body and that the matching external 21mm finder, if offered, is included and free of haze.","specs":"Specifications data is sparse for this listing; the lens is documented here as a 21mm f\/4.5 Biogon for Contax, with no further verified specifications to summarise.","faq":[{"q":"What is a Contax 21mm f\/4.5 Biogon worth today?","a":"Based on the limited UK auction record available, one verified hammer price of £200 has been recorded, which is the clearest reference for current value at saleroom level."},{"q":"How much does a Contax 21mm f\/4.5 Biogon sell for at auction?","a":"The single tracked UK auction sale realised £200 at the hammer, so wholesale auction prices currently centre on that figure, with clean and complete examples capable of exceeding it."},{"q":"What should I check before buying one?","a":"Prioritise checking for fungus, haze, oil on the aperture blades, coating condition and smooth focus action, since these are the most common faults in vintage Biogon-type wide-angles."}],"confidence":35,"reasoning":"Only one verified sale and no specs or variant data are provided, so confidence is capped well below 50 per rule 8."}