Film Light Meter

A camera without a working meter is not a broken camera, it is a camera waiting for a reading. A phone light meter gives you one, then does the arithmetic.

Point the phone at your subject and the ambient light sensor reads the light falling on it, in lux, and turns that into an exposure value. If the scene is better measured from where you stand, the reflected mode takes a reading through the camera instead.

- Incident reading from the ambient light sensor
- Reflected reading taken through the camera
- Send either reading straight to the calculator
- A full table of aperture and shutter pairs for your ISO
- Aperture priority or shutter priority
- ND filter compensation in stops
- Reciprocity presets for common film stocks
- Calibration offset in tenth-stop steps, up to three stops

Long exposures are where film stops behaving, so pick your stock and the metered time is corrected for reciprocity failure before you open the shutter. If your trusted light meter disagrees with the phone, nudge the calibration offset until the two match and every later reading inherits it.

Sensor accuracy varies between phones, which is what the offset is for. Everything runs on the device, with no account and no sign-in.