The Olympus Pen is a half-frame 35mm camera line introduced by Olympus in 1959, exposing two 18×24mm frames in the space of a standard 24×36mm negative. The series was positioned as a compact, economical alternative to full-frame 35mm cameras, doubling the exposure count on a standard roll of film.

With only a single UK auction record on file, the price evidence for what an Olympus Pen is worth is thin: one example sold for £50 at hammer in April 2023. That figure is a wholesale saleroom result rather than a retail asking price, and today values vary widely by specific Pen variant and condition, so a one-sale sample should be treated as indicative only.