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.

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.