To produce a better understanding of your proposed camera view/s, an industry standard has been produced called ‘DORI’ which is an acronym for:
Detect
Observe
Recognise
Identify
These measurements are calculated by several factors, these being:
Camera Installation height
Distance/target required from camera
Target height
Sensor format
Focal length (Lens)
Camera resolution
These particulars would produce not just the ‘FOV’, (Field of View) along with ‘Horizontal angle’. But the ‘DORI’ measurements/scale, giving a better understanding of your views.