# Reciprocity > Photography exposure calculator for ISO, aperture, shutter speed, and film data. (iPhone/iPad app by Scott Lagaly.) - Source: https://appshunter.io/ios/app/reciprocity/id392805740 (this page in markdown: same URL + `.md`) - Developer: [Scott Lagaly](https://appshunter.io/developer/392805743) - Category: Photo & Video - Price: $0.99 with in-app purchases - Rating: 2.00/5 from 1 App Store ratings · 6 written reviews indexed - Age rating: 4+ - Requires: iOS 8.0 · 16 MB - Languages: English - Released: 2010-09-23 - Data updated: 2026-06-10 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/reciprocity/id392805740/reviews.md ## What is Reciprocity? Reciprocity easily calculates exposure settings for great pictures every time. Great for anyone, from beginners to seasoned photographers. Features: * Instantly calculate Exposure value, ISO speed, Aperture, or Shutter Speed * Enter values either directly or via a slider * Option to choose Exposure value from a list of common scenes * Convert exposure settings between different cameras or film speeds * Save the reciprocity failure values of multiple films for future use * Round exposure stop values to 1/2, 1/3 or both * Built-in timer for exposure longer than 2 seconds * Detailed user guide to help beginners make use of their camera's manual settings ## Key features - Calculate Exposure Value, ISO, Aperture, Shutter Speed - Convert settings between cameras/film speeds - Save film reciprocity failure values - Round exposure stop values - Built-in timer for long exposures - Detailed user guide ## Pricing and in-app purchases Base price: $0.99. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Additional Features and Remove ads | $0.99 | one-time | ## Recent user reviews (6 of 6) All indexed reviews: https://appshunter.io/ios/app/reciprocity/id392805740/reviews.md ### 2/5 — Native shutter speeds are off! *2013-08-09, version 1.2.1* Native shutter speeds in full stops are: 1sec,1/2,4,8,15,30,60,125,250,500,1000 **Developer response:** Version 2.0 now uses native shutter speeds, and also allows you to select between 1/2, 1/3, or both 1/2 and 1/3 stops. ### 5/5 — great app *2013-01-05, version 1.2* works well. Good for easy calculation of shutter speeds in different ISO ranges. That is really perfect for night shots. Like the shutter counter. An dddition of big stopper filter would be great. Thanks ### 2/5 — Filter function not working *2012-12-27, version 1.2* I just bought the Additional Features module for my iPhone 5, and the Filter function is not working. If I try to add a new filter (I need more EVs than the default filters provide), nothing happens -- a new filter is NOT added to the list. Scott, can you fix this? ### 5/5 — I love cinematography, I hate math *2012-09-23, version 1.2* It's always nice to have calculators like this on set. Without it, I'd imagine making a huge fool out of myself doing the math in head or by hand.. Greatly appreciated! ### 4/5 — Great App *2012-04-07, version 1.2* Works as you would think. I wish it would measure Ev, though I guess that would make it more of a meter. It's good stuff! ### 4/5 — Good App *2011-04-20, version 1.0* This is a one of the best apps I've found for figuring general reciprocity failure for most films. While I have only used it with a couple of films, I have found it to be accurate. This app would be great if it had a timer built in. Right now I have to exit the program, start a clock/timer program for timing the exposure. It would be great to have a timer that would automatically enter the shutter time then when the start button is hit it would count down from between 5 to 10 seconds. Then make a warning sound to start the exposure, then make another warning 5 to 10 seconds before the the end of the exposure. There is room at the bottom for the timer. Thanks! ## Frequently asked questions about Reciprocity ### What is Reciprocity used for? Reciprocity is a photography tool that helps you easily calculate exposure settings like ISO, aperture, and shutter speed. It also allows you to convert settings between different cameras and save film data for future reference. ### How much does Reciprocity cost? Reciprocity is a paid app, available for $0.99. This one-time purchase grants you access to all its features for calculating photography exposure settings. ### What devices does Reciprocity support? Reciprocity is designed for iOS devices, including iPhone, iPad, and iPod. It is compatible with a range of Apple mobile devices. ### What is the age rating for Reciprocity? Reciprocity has an age rating of 4+. This indicates it is suitable for users of all ages, with no content restrictions. ### When was Reciprocity last updated? The latest version of Reciprocity, 2.0, was last updated on September 18, 2017. While it has been a while since the last update, the core functionality remains relevant for photographers. ### Does Reciprocity have a free trial? As Reciprocity is a paid application with a one-time purchase price of $0.99, there is no free trial period. You can purchase it directly to access its features. ### How does Reciprocity handle long exposures? Reciprocity includes a built-in timer specifically for managing exposure times longer than 2 seconds. This feature helps ensure accurate exposure for astrophotography or other low-light scenarios. ### Can Reciprocity help beginners understand manual settings? Yes, Reciprocity comes with a detailed user guide designed to assist beginners in understanding and utilizing their camera's manual settings for better photography. ## Version history (last 5 releases) ### 2.0 — 2017-09-18 This app has been updated by Apple to display the Apple Watch app icon. * This major update to Reciprocity has the same classic look and functionality, but has been rebuilt under the hood for forward compatibility and future improvements. * As requested, you may now choose to round values to 1/2, 1/3 or both exposure stops in settings. * Reciprocity failure can now be saved for multiple films and be selected as needed. * Reciprocity is now universal and will work on your iPad too! ### 1.2.1 — 2013-05-12 Changed filter EV adjustment maximum per filter from 5 to 12 stops Minor fixes for iPhone 5 screen dimensions ### 1.2 — 2011-10-03 * Added countdown timer * Improved app startup * Added user guide, can be opened in iBooks * ISO slider improvements ### 1.1 — 2011-04-30 Added code to request user to rate the app Added In App Purchase to: * Remove ads * Add filter adjustment settings * Add reciprocity failure adjustment settings ### 1.0 — 2010-09-23 No release notes. ## Apps similar to Reciprocity | App | Rating | Price | Category | | --- | --- | --- | --- | | [MPro](https://appshunter.io/ios/app/mpro/id540292572) | 5.0 (2) | $1.99 | Photo & Video | | [Darkroom Formulas](https://appshunter.io/ios/app/darkroom-formulas/id807461207) | 3.0 (3) | $5.99 | Photo & Video | ## More apps by Scott Lagaly - [John Allen's Timesaver Puzzle](https://appshunter.io/ios/app/john-allens-timesaver-puzzle/id1050764647) - [John Allen's Timesaver Lite](https://appshunter.io/ios/app/john-allens-timesaver-lite/id1162009059) All apps by Scott Lagaly: https://appshunter.io/developer/392805743 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*