Per-Device Calibration via 18% gray
One-tap calibration against a known sunlit scene to dial out sensor offset.
Where to find it
Settings Calibration Run calibration
Summary
Calibrates the meter to your specific phone. Point the camera at a familiar Sunny 16 scene, tap once, and the app captures a calibration offset that gets applied to every reading from then on.
Detail
How it works
What it does
Phone camera sensors vary slightly from one device to the next, even within the same model. This calibration step measures your specific phone's offset against a known reference and applies it to every future meter reading so the numbers match what a dedicated meter would say.
How to run it
Find a scene that matches the Sunny 16 rule: front-lit subject in clear midday sun. Tap the Run Calibration button and hold the phone steady while it takes a measurement. The app compares what it read to what Sunny 16 predicts, and the difference becomes your calibration offset.
When to re-run
Once is enough for most users. Re-run if you switch phones, if you change a major Camera2 setting (Pro precision toggle, AWB), or if you suspect the readings have drifted. The offset is stored per profile so different cameras you switch between can have different offsets.
What it does not do
It cannot fix lens variation between different cameras you might attach to the phone. The offset corrects sensor behavior, not optical quirks. For lens-specific compensation, use the filter factor or expired-film modal.