Light meter
Uses Camera2 sensor data, not a screen-brightness estimate. Average, spot, and compare modes. EV compensation, lock-and-recompose, multi-reading averaging, and a per-device calibration slider. Benchmarked against a Sekonic L-408.
Sprocket
A film photography companion app for Android.
Light meter · reciprocity · golden hour · dev timer · roll logger · chemicals · reference library
Coming soon to Google Play
What it does
Most existing tools answer one of these questions and stop. Sprocket answers all of them.
Golden hour
Sunrise and sunset phases (civil, nautical, astronomical) for any city. Live countdown, gradient phase display, and an optional notification so you have time to get there.
Reciprocity calculator
Corrected exposure times for 60+ film stocks. Both calculation modes, a graph, and the underlying formula. Works for Portra, HP5, Provia, and a range of less-common stocks.
Development timerPro
Multi-step kit timing with agitation prompts and haptic cues. A dev-times database covering 170+ film and developer combinations. Create and save custom timer sequences.
Roll loggerPro
Log aperture, shutter, lens, focal length, optional GPS, and notes per frame. Track a roll from loading to archive. Browse history by film stock or compare rolls side by side.
Chemical trackerPro
Tracks what is in your darkroom, when it was mixed, and when it expires. Usage logs, shelf-life alerts, and a mixing calculator for working-strength dilutions.
Film stock database
85 stocks. Browse and filter by type, format, and ISO. Compare two stocks side by side or browse curated lists: black-and-white, colour negative, slide film, and more.
Camera manuals
Upload camera manuals as PDFs and read them inside the app. The first four uploads are free; unlimited with Pro.
Built by a film photographer, for film photographers.
Sprocket started out of frustration with context-switching. Development times on one website, reciprocity corrections buried in a forum from 2009, the roll log in a notebook, the light meter in a separate app. Sprocket puts it all in one place, covering only what actually matters for shooting and developing film.
The light meter reads native Camera2 sensor data from the hardware. It has been benchmarked against a Sekonic L-408 Multimaster across a range of lighting conditions. If your phone reads consistently high or low, there is a per-device calibration slider. A methodology page in the app explains exactly how the EV formula works.
There are no accounts, no Sprocket servers, and no cloud sync. Your rolls, frames, chemicals, GPS coordinates, and notes live on your phone and nowhere else. The only data that leaves the device is anonymous crash reports. You can switch those off in Settings. The privacy policy is one page.
Free and Pro
The core tools are free. Pro unlocks the features that matter most if you develop your own film.
Free
Free
No account. No time limit.
- Full light meter, all modes
- Reciprocity calculator, 60+ stocks
- Golden hour, all features
- Sunny 16 guide
- Single-step timer and safelight mode
- Darkroom and dev guides
- Film stock browser, 85 stocks
- Camera manual uploads, first 4 free
- Chat assistant (your OpenRouter key)
- 1 roll, 1 chemical
Pro
$4.99 USD
One-time purchase. Not a subscription. Yours forever.
- Multi-step development timer
- Dev times database, 170+ entries
- Unlimited rolls and frame logging
- Full chemical tracker
- Locations and photo trips
- Film stock compare and curated lists
- Unlimited manual uploads
- Push notifications