Angle of view is the angular extent a lens captures horizontally, vertically and diagonally. It follows from the lens focal length and the sensor size, and it decides how wide a camera sees and how much detail each part of the scene holds. A wider view covers more area with fewer pixels per subject.
Two cameras with the same resolution can produce very different footage depending on their angle of view. One shows a whole parking lot and cannot identify a face; the other shows one doorway clearly.
Angle of view and field of view
The two terms are often used interchangeably. Angle of view is the angle at the lens; field of view is the distance that angle covers at the subject, in meters or feet. A wide angle spanning 10 meters at the door spans 40 meters at the fence, and detail falls away with it.
Choosing the angle
Start from the job: a doorway, a till, a plate lane or an overview. Decide how large a person must appear in the image, measure the distance, and pick the lens that produces that size. A varifocal lens tuned on site is the practical way to settle the angle after mounting.
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