Video camera having an automatic focusing system

Claim 1

A video camera comprising: a camera tube; a main optical system including a focusing lens and a master lens, for directing an external incident light towards said camera tube along a first light path; an automatic focusing system having a sensor which obtains a focusing information responsive to an incoming light to said sensor, for carrying out an automatic focusing by displacing said focusing lens responsive to the focusing information; light separating means arranged in said first light path for reflectively separating a first portion of said external incident light as a separated light which travels along a second light path; mirror prism means comprising a pair of prism elements which are put together so that a meeting surface of one prism element meets a meeting surface of the other prism element, one of said meeting surfaces being provided with a mirror part which has an elongated rectangular shape and an area which is smaller than said one meeting surface, said prism mirror means being arranged in said second light path so that said mirror part reflects and directs a second portion of said separated light towards said sensor, said second portion of said separated light travelling along a third light path; and an optical type viewfinder arranged in said second light path for receiving a remainder of said separated light after said second portion is separated from said separated light by said mirror prism means, said external incident light continuously and simultaneously reaching said camera tube, said sensor and said optical type viewfinder along said first, second and third light paths, respectively.