Film Light Meter: Reciprocity
Long Exposure & ND Calculator
Meter with your camera, then correct long film exposures for reciprocity failure using the manufacturers' own datasheets.
Light meter and reciprocity calculator for film photographers. Point your phone at the scene, pick your aperture and film, and get the exposure, already corrected for reciprocity failure from the manufacturer's datasheet.
What it does
- Light meter: reads the scene through the camera, shows EV and the shutter time for your aperture and film ISO; tap to hold a reading
- Calibrate once against a meter you trust with exposure compensation
- 30 black & white, colour negative and slide films, with corrections from official datasheets only and the source shown for every film
- Manual metered-time input from 1/1000 s to hours
- Corrected time, stops added and the datasheet note
- Clear warnings when a time is beyond the datasheet's range
- Dark by default for night work
Free
- Light meter with reciprocity correction
- All built-in films and manual time input
PRO (one-time purchase, no subscription, no ads)
- ND filter stacking (stops or factors like ND1000), applied before reciprocity
- Exposure countdown timer with a notification when it ends
- Favourite films
- Custom films with your own exponent or table
Pro is a single in-app purchase with Family Sharing.
Phone metering and datasheet values are a starting point. Bracket important exposures.
Support
Restoring Pro: open Settings in the app and tap Restore Purchases, signed in with the Apple ID you bought it with. Pro is shared with your family through Family Sharing.
Your data: everything stays on your iPhone. The app has no account and makes no network requests, so there is nothing to sync or delete on a server.
Questions, bugs or ideas: write to boris.stiner@gmail.com. Please mention the app name and your iOS version.
Privacy
This app collects no data. No account, no tracking, no ads, works offline. Read the privacy policy.