The angular aperture of a lens is the apparent angle of the lens aperture as seen from the focal point:
where
- is the focal length
- is the diameter of the aperture.
Read more about Angular Aperture: Relation To Numerical Aperture
Famous quotes containing the word aperture:
“Animals used to provide a lowlife way to kill and get away with it, as they do still, but, more intriguingly, for some people they are an aperture through which wounds drain. The scapegoat of olden times, driven off for the bystanders’ sins, has become a tender thing, a running injury. There, running away ... is me: hurt it and you are hurting me.”
—Edward Hoagland (b. 1932)