Silverlog Reciprocity
Film Long Exposure Calculator
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Compensate for reciprocity failure in seconds. Select your film stock, enter your metered time, and get the corrected exposure instantly.
Silverlog Reciprocity calculates corrected exposure times for long exposures on film, compensating for reciprocity failure — the point where film loses sensitivity during extended exposures.
HOW IT WORKS
Select your film stock from a comprehensive database covering Kodak, Ilford, Fujifilm, Fomapan, CineStill, Lomography and more. Enter your metered exposure time and instantly see the compensated time you should actually use.
Calculations use manufacturer-published reciprocity data or established empirical formulas, and each correction shows which method was used: interpolation from a published data table, or a Schwarzschild exponent formula.
FEATURES
• Over 70 film stocks with reciprocity data
• Instant calculation — no submit buttons, results update live
• Method shown with each correction — data table or Schwarzschild exponent
• Built-in countdown timer for the corrected exposure
• Favourite and recent films for quick access
• Works offline — no internet connection needed
• Clean, focused interface designed for use in the field
• Dark mode support
BUILT FOR PHOTOGRAPHERS
Whether you're shooting Velvia at sunset, Tri-X under moonlight, or Delta 3200 in a cathedral, Silverlog Reciprocity gives you the corrected time without fumbling with charts or guesswork.
Part of the Silverlog photography toolkit. No account required. No data collected.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
Updated for iOS 27, with the latest version of the app's frameworks. Everything works as before.
The developer, Simon Westgate, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Simon Westgate
- Size
- 42.2 MB
- Category
- Photo & Video
- Compatibility
Requires iOS 16.4 or later.
- iPhone
Requires iOS 16.4 or later. - iPad
Requires iPadOS 16.4 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
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- Copyright
- © Silverlog 2026