Two ways to meter
Spot reads one point — a face, a shadow, the one tone that matters — for scenes where the light won't agree with itself. Matrix reads everything at once and averages it, quicker when the scene is already even. Switch mid-shoot; nothing else about the workflow changes.
Matched to your camera
No two cameras meter a scene identically, so a generic reading is only ever a starting point. Calibrate to your own body from a library of film cameras and the numbers on screen match what your camera will actually record.
Hold and capture
Meter the shadow, lock it, then recompose on the subject — the reading doesn't drift with the frame. Useful for backlit portraits, or comparing two spots before you commit to one. Export the reading as a card once you're happy with it.
Made for film photographers
Built for the way film actually gets shot: 35mm or medium format, one frame at a time, no screen to check afterward. Students working through the Zone System get a meter that shows the reasoning, not just a number.
Frequently asked
Can a phone app replace a handheld light meter?
For most work, yes. Lumo reads spot and matrix light the same way a handheld meter does, calibrated to your specific camera body. It doesn't take incident readings (light falling on the subject rather than reflected off it) — for reflected-light metering on 35mm and medium format, a phone already in your pocket beats a meter left at home.
What's the difference between spot and matrix metering?
Spot metering reads a single, narrow point in the frame — a face, a shadow, whatever tone matters most. Matrix metering reads the whole scene and averages it into one number. Use spot when the light is uneven and you need to protect one tone; use matrix when the light is already even and you just want a fast, general reading.
Does Lumo work for medium format cameras?
Yes. Lumo's camera library includes medium format bodies alongside 35mm, and calibrating to the right one adjusts the reading to match how that camera actually meters. If your exact body isn't listed, Lumo Pro lets you build a custom profile for it.
Do I need Lumo Pro, or is the free version enough?
The free version covers the core of the app: spot and matrix metering, 30+ camera profiles, and exporting a reading as a card — enough for most shooting. Lumo Pro adds themed dials, custom camera profiles, and full control over the meter's accent colour. It's a one-time £1.99 purchase, not a subscription.
Does Lumo work offline?
Yes. Metering happens on your device — there's no server involved and no connection required once the app is installed. You'll need one the first time, same as any App Store download, but after that it works anywhere.
