The FoV is related to the CMOS size and the focal length of camera lens.
- The horizontal FoV = 2 × arctan（w / 2f）
- The vertical Fov = 2 × arctan（h / 2f）
- The FoV = 2 × arctan（d / 2f）
- w is the width of the CMOS, h is the height of the CMOS, d is the diagonal of the CMOS.
For example, the Zenmuse P1 35mm camera, The size of its CMOS is 35.9×24 mm, so its
horizontal FoV = 2 × arctan（35 .9/ 70）= 54.3°.