f/oss

f/oss is a free light meter for film photography — rebuilt from the ground up as a fully native app.

Point the spot-metering circle at your subject and read the exposure instantly. f/oss measures true photometric luminance through your iPhone's camera and is calibrated against professional reference meters.

FIVE METERING MODES

• Aperture Priority — set f-stop and ISO, get your shutter speed

• Shutter Priority — set shutter and ISO, get your f-stop

• Exposure Value — read the scene's EV directly

• Cine — shutter angle and frame rate for filmmakers

• Manual — check your chosen settings against the metered scene

BUILT FOR REAL CAMERAS

• Camera profiles: save your bodies with their actual shutter and bias limits

• Full, half or third stop increments

• Configurable shutter, aperture, ISO and exposure bias ranges

• Reference lock: freeze a reading and measure scene contrast in stops

• Exposure lock for recompose workflows

ACCURATE

• True spot metering of exactly the circle you see

• Full-color light analysis — reads saturated LED and neon light correctly

• Verified against professional meters from daylight to low light

FREE, NO SUBSCRIPTION

Every feature is free, forever. If f/oss saves your shots, there's an optional tip jar — that's it.