About Zone Light Meter

What it is

Zone Light Meter turns your Android phone into a calibrated handheld light meter for film photography. It reads light through your phone's camera, calculates aperture and shutter settings, accounts for the quirks of analogue film (reciprocity failure, bellows extension, IR filters, expired stock), and logs every shot so you can match it back to a scan or contact sheet later.

What makes it different

Most light meter apps stop at the reading. This one is designed around a specific belief: that the meter should teach you. Every modal has a help icon. Every recommendation explains what it is doing and why. The zone system, the sunny 16 rule, reciprocity crossovers, hyperfocal distance, multi-spot biasing: all of it is spelled out in plain language, with the math available if you want to see it.

Local-first and private

There is no account. There is no cloud sync. There are no third-party trackers. Every reading, every roll, every shot you log lives in a database on your phone, which you can export to CSV at any time. The app works fully offline. The website you are reading right now does not run analytics either.

The documentation

This site documents 109 features across 20 sections. Of those, 101 are fully shipped, and 8 are partially shipped. Each feature has a page that explains what it does, when to use it, and where to find it in the app.

The documentation is generated from the same data source the app itself reads to render its in-app help modals. If a feature changes in the app, the page you are reading also changes. Nothing drifts.

Who builds it

One developer, working in their spare time, between rolls of film. Feedback is welcome. The email is on the support page.

Platform availability

Android first, because the camera APIs were the right starting point. iOS port is in early development. Most features document the current Android behavior. When iOS ships, per-feature notes will mention any differences.