A light meter for film cameras and a lux meter for everything else, in one app. The camera is the sensor; nothing leaves your phone.
Questions, bug reports and feedback: developer.barseghyan@gmail.com. We usually reply within two business days. If you report a wrong reading, please include your iPhone model, the lighting (sunlight, overcast, indoor LED) and what a reference meter or camera showed.
A phone camera is a good meter, not a lab instrument. Some iPhone models ship with a measured profile for the rear camera (currently iPhone Air), with an expected error of about ±1/3 stop (±10% lux). Every other iPhone and camera gets an automatic profile on first launch, about ±1/2 stop (±25%), which becomes about ±1/3 stop after you calibrate against your own lux meter or camera. The app always shows its expected error next to the reading: green for ±1/3 stop, amber for ±1/2 stop.
Settings → Calibration. Put the phone next to your lux meter, screen up, so both see the same light, or compare an exposure reading with your camera's built-in meter, then enter what yours shows and tap Apply correction. Outdoors in direct midday sun you can also run the Sunny 16 check: expect about EV 15 at ISO 100.
Spot meters the small circle; average meters the whole frame, centre-weighted. Long-press the circle to switch. A spot meter reacts to what is inside the circle, so moving from a bright wall to a dark doorway changes the reading by several stops. Point at one surface, hold still for a second, then read or tap Hold.
Light is one number (EV); aperture and shutter are two settings that can produce it. You choose the one that matters for the picture (aperture for depth of field, shutter for motion) and the app meters the other. Change the locked value with the arrows or by swiping; tap the metered card to swap which one you set. The "Same exposure" row lists every pair that gives the same exposure; tap one to use it.
If the result is outside your camera's shutter or aperture range, it turns red and a suggestion appears, for example "Open to f/2.8" or, when no setting fits, a push or pull ISO for the same film.
Lux mode uses the front camera by default: lay the phone flat, screen up, where the light lands. Switch to the rear camera to measure the light on a surface you point at.
Both meters (exposure and lux), spot and average metering, every film and ISO, the Same exposure row, calibration, up to 3 cameras and 10 saved readings. No ads and no time limit.
Pro is a one-time purchase, no subscription: unlimited cameras, films and saved readings, reciprocity correction for long exposures, colour temperature in Lux mode, CSV export, and future Pro features. To restore on a new phone, open Settings → Restore purchases while signed in with the same Apple Account.
Film loses sensitivity during long exposures (reciprocity failure). For exposures of 1 s and longer, Pro applies the film's published correction and shows the extra stops under the shutter value. Films marked "approximate" use a generic curve.
"Ranging" means the camera is adjusting its exposure to the scene; wait a moment. If you move the phone quickly, the reading pauses until it is steady again. "Low light" means the scene is near the camera's limit, so expect about ±1/2 stop. "Too dark" means the light is below what the phone camera can measure, and the app shows the lowest level it can read instead of a guess. Very bright direct light sources (the sun, a bare bulb) can clip and are not meterable; meter a lit surface instead.
Any iPhone with iOS 17 or later. The rear camera is used for exposure and for lux on a surface; the front camera for incident lux with the phone lying flat.
No. No account, no analytics, no ads, no network access. Readings stay on your phone. See the Privacy Policy.