Lighting is a highly technical craft. Even though it isn't necessary to know the number of footcandles or lux that a light gives off at a certain distance, or how a light's CRI will affect the final image, to light a shot effectively, you can bet that the most discerning cinematographers and their gaffers are absolutely thinking about those technical characteristics. Even though that type of information can be intimidating for beginning (and even intermediate) filmmakers. 

ARRI's free Photometrics app puts all that information in your back pocket, making it a perfect companion when working with any number of ARRI light fixtures, including the Skypanel, L-Series, M-Series, or Orbiter. 

Available to download for iOS or Android, the app provides all the technical data about ARRI lights you'll need in your back pocket. While the app itself doesn't control any fixtures remotely—that's actually done through ARRI's Stellar app—it has a ton of useful information. 

You have quick access to luminous output, beam diameter, beam angle, luminous distribution graphs, camera exposure, and aperture information, and best of all, flood, middle, and spot photometrics. 

The app also supports a wide range of other information such as color temperature, CRI, protection rating, dimming, dimensions, weight, and power draw of each light among others. On top of that, there are DMX conversion and CCL calculators as well as a way to compare different ARRI lights.

Even if you don't regularly use ARRI lights, it's a good way to familiarize yourself with their lineup when you do. You can download the latest version of the app here