See how much light a spot gets, using your phone's camera.
Switched off
The light meter has been turned off. If you would like it back, ask the person who runs your Plant Journal.
Measure a spot
Hold a plain white sheet of paper where the plant sits, flat, facing the way its leaves face.
Fill the whole camera view with the paper. No hands, shadows or edges.
Take the photo with your phone's normal Camera app. Then tap "Choose photo" below and pick it from your library.
Why not just take it here? On iPhone, photos taken inside a web page lose the camera details the meter needs. Photos from the Camera app keep them. The photo stays on your phone and is forgotten after reading.
Type in the photo's details
In the Photos app, open the photo and swipe up (or tap the ⓘ button). You will see a line like ISO 50 · f/1.78 · 1/120. Type those three numbers here.
This spot
Very dimLowMediumBrightDirect sun
How this was worked out
This is an estimate, usually within about 40%. That is enough to tell low from medium from bright light, but not to compare two spots that are close. Light changes with the time of day, the weather and the season, so measure around midday.