FOCAL LENGTH


Meaning of FOCAL LENGTH in English

Optics.

1. the distance from a focal point of a lens or mirror to the corresponding principal plane. Symbol: f

2. the distance between an object lens and its corresponding focal plane in a telescope. Also called focal distance .

[ 1745-55 ]

Random House Webster's Unabridged English dictionary.      Полный английский словарь Вебстер - Random House .