How to calculate FOV?

Question

Initial Context

I am developping an augmented reality application location based and I need to get the field of view [FOV] (I just update the value when the orient

Answer 1

Apple has also released a list with all camera specification details including FOV (Field of View).

https://developer.apple.com/library/ios/documentation/DeviceInformation/Reference/iOSDeviceCompatibility/Cameras/Cameras.html

The values match the values that can be retrieved using:

float FOV = camera.activeFormat.videoFieldOfView;