ReciproMeter

ReciproMeter is a free light meter for film photographers who need dependable long-exposure calculations. Use your iPhone camera to read exposure metadata, select your film stock and aperture, and get an immediate shutter recommendation. When exposure times run long, ReciproMeter applies reciprocity correction using official manufacturer data whenever available. For films where official datasheets stop short, ReciproMeter keeps the distinction clear: • Official manufacturer reciprocity data • Optional community-sourced long-exposure guidance • Optional experimental estimates, clearly labeled as lower confidence Features: • Live camera preview, visible by default, with an optional full-screen exposure view • Camera calibration, steadier readings, and low-light guidance • Manual EV and external meter input with reference aperture and ISO • Exposure lock for holding a reading while composing • Neutral-density compensation, then reciprocity on the longer time • One-stop exposure bracket that follows the film's reciprocity curve • Favorite films and a built-in library with correction charts and source links • Saved film, aperture, ND, and EI presets • Exposure notes with frame numbers and development results • Community and experimental long-exposure tiers as separate opt-ins • Metering ISO / EI override for push-pull workflows • Bulb timer with preparation delays, optional audible cues, and a Lock Screen countdown • Dark mode, light mode, or system appearance Privacy: ReciproMeter does not take or store photos. It only reads camera exposure metadata needed to estimate ambient light. An App Open ad may appear over the loading screen at launch, or on a return to Films, Notes, or Settings after you have been away for at least a minute, at most three times a day. Active metering, timers, note editing, and purchases are protected. The first launch is ad-free. The loading screen shows the Remove Ads Forever price when available. Remove Ads Forever is an optional one-time in-app purchase. It removes all advertising with no subscription or expiration. Purchase or restore it in Settings. Advertising privacy choices remain available from Settings where required.