The Jupiter F-21 is a Soviet-era 21mm subminiature spy camera designed for covert photography. It is best known for its compact form factor and clockwork-driven film advance, intended for concealed use rather than general photography.

Sales data is extremely limited: a single UK auction hammer result from June 2022 saw a Jupiter F-21 sell for £150, and that figure remains the only reliable wholesale reference point as of today in 2026. With just one record on file, it is difficult to define a true price range or median, and condition, completeness of accessories (cassettes, winder key, viewfinder) and originality will materially affect what any given example is worth at saleroom level.