The Corfield Periflex 3a is a 35mm film camera made by the British manufacturer K.G. Corfield. It takes Leica-thread (M39 screw-mount) lenses and uses the distinctive periscope-style reflex viewing system from which the Periflex range takes its name, positioning it as a domestically produced alternative to imported rangefinders when new.

At recent UK auction, hammer prices for the Periflex 3a have ranged from about £38 to £210, with a median around £110 — these are saleroom results and so sit below typical dealer retail. The most recent sale in 2025 reached £214, suggesting that in today's market clean, working examples with an intact periscope mechanism command the top of the range, while rougher bodies sell for well under £50. Condition and completeness drive most of the spread in what this camera is worth.