Reciprocity easily calculates exposure settings for great pictures every time. Great for anyone, from beginners to seasoned photographers.

* 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

What’s New

Version 2.0

* 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!

Ratings and Reviews

2.0 out of 5
1 Rating

1 Rating

Chakkababy ,

Native shutter speeds are off!

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.

tintypes ,

Filter function not working

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?

Onlyme2006 ,

Good App

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!


Scott Lagaly
15.5 MB

Requires iOS 8.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
In-App Purchases
  1. Additional Features and Remove ads $0.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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