
f/oss
Light meter for photography
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Free
About
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 is an optional tip jar.
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What's New in f/oss
2.0.2
August 6, 2026
• Added an optional tip jar and an in-app FAQ • Smoother metering readout with animated digits • Steadier stop selection with less flicker in the reading • Fixes and refinements throughout
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