ReciproMeter

ReciproMeter is a 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 metering with full-screen exposure view • Exposure lock for holding a reading while composing • Built-in film library with official reciprocity sources • Community and experimental long-exposure tiers as separate opt-ins • Metering ISO / EI override for push-pull workflows • Bulb timer for corrected long exposures • Dark mode, light mode, or system appearance