Focal Length – The focal length of the lens is the distance between the lens and the image sensor when the subject is in focus.
Focal Length is the distance between the pole and the principal focus of a spherical mirror.
Focal Length…
What is Focal Length?
फोकस दूरी (Focal length) ध्रुव एवं फोकस के बीच की दूरी को गोलीय दर्पण की फोकस दूरी या फोकसांतर कहा जाता है।