What is Angle of View?

The Basics:

The Angle of View refers to the maximum angle that a lens can see, based on a combination of focal length and camera sensor.

A Little More Detail:

Lenses with a higher focal length - let’s say 100mm - are able to hone in on things further away; but they also have a narrower angle of view. By comparison, shorter focal lengths, such as a fisheye lens, have a much wider angle of view.