Talk:Field of View

in the formula $FoV=2*atan{\frac {35}{2*FocalLength}}$

The "35" should be some "length" because it is divided by a length, and should become unitless. Of course the length is the size of a standard negative: 35mm. If you want to "ignore units" as most americans like to do, it should not that "Focal length" is in mm. But more accurate is:

$FoV=2*atan{\frac {35mm}{2*FocalLength}}$