Crisp Light Meter

Crisp Light Meter converts your iPhone camera's auto-exposure settings (shutter speed, ISO and aperture) into illuminance, then estimates a light's luminous flux from the measuring distance and beam angle. Light meter • Live illuminance in lux or foot-candles (fc) • Logarithmic scale showing dim, indoor, bright and daylight levels • EV100, uncalibrated lux, calibration factor, and the average, minimum and maximum of recent readings • Lock the reading to note it down • Works with both the front and rear cameras Lumen estimate • Estimates flux with Φ ≈ E × d² × Ω • Pick the distance on a wheel, in meters or feet • Common beam angles in one tap, or set any angle • Multipoint sampling averages several readings to reduce the effect of uneven light Calibration • Compare against a reference lux meter; front and rear cameras keep separate calibration factors • Calibration applies immediately History • Save readings with distance, beam angle and calibration factor • Add a note to any record Privacy • The camera is used only to read exposure settings. No photos or videos are captured, saved or uploaded • Everything stays on your device. No account, no network access, no data collection About accuracy A phone camera is not a professional instrument. Uncalibrated error can reach ±30%, and the device, light source and orientation all affect results. Use this app for everyday reference; it does not replace a professional lux meter or integrating sphere. Calibrating against a reference meter greatly improves accuracy.