"Bart van der Wolf" writes:

Yes, if you know the sensor size, at infinity focus it's:
ATAN( sensor_size / 2 / focal_length) * 2 = FOV

Of course, the "sensor_size" in the above can be the horizontal width
or the vertical height of the sensor, which gives you horizontal and
vertical field of view. Using the sensor diagonal tells you the angular
covering power of the lens.

Dave