How to measure
Pick a method on the Measure screen. Use paper when you can.
- Lay the phone face up where you want to know the light.
- Cover the front camera with a sheet of printer paper.
- Keep still until the reading settles.
- Put a sheet of white paper where the light lands.
- Point the back camera at the paper from about 25 cm.
- Keep your shadow off the paper.
- No paper needed.
- Lay the phone face up, front camera to the light.
- Treat the number as rough.
Calibrate
Readings are labelled as estimates until you calibrate. After calibrating, they show your active profile instead.
With a light meter
- Put the meter and your phone in the same spot.
- Tap Calibrate on the Measure screen.
- Type what your meter reads and tap Set reference.
Your own paper
Printer paper varies. Calibrate the sheet you actually use for Flat or Card, and keep using that sheet.
Why phones differ
Apple's cameras expose about 0.4 EV darker than a classic meter, from 0.1 to 0.8 EV depending on the model. Luxwise corrects for each model.
Public iPhone photos used to build those per-model corrections.
Light meter apps also differ from each other. A one-point calibration against a meter you trust brings your numbers in line.
How accurate is Luxwise?Restore purchase
Luxwise Pro is a one-time purchase. On a new device or after reinstalling, open Settings with the gear button and tap Restore purchases.
Use the same Apple Account you bought Pro with. With Family Sharing, your family group can restore it too.
Export CSV and backups
In Settings you can tap Export CSV to open your readings in a spreadsheet, or Back up to save a .luxwise file you can restore later.
With optional iCloud sync, your data is also kept in your own iCloud.