Patent ID: 7619189

Claim:
An imaging apparatus, comprising: an optical system that focuses light from a subject and over which focus control is executed; an optical path separation unit that separates the light from the subject focused by the optical system into at least a first light beam and a second light beam; a first imaging unit that includes an image sensor, and converts the first light beam to an electric signal and outputs the electric signal as a first signal; a second imaging unit that includes an image sensor, and converts the second light beam to an electric signal and outputs the electric signal as a second signal; an optical-path length changing unit that changes an optical-path length of the second light beam by moving the second imaging unit along an optical axis of the second light beam; a control unit that generates a contrast evaluation value of the second signal output from the second imaging unit while controlling the optical-path length changing unit to change the optical-path length of the second light beam, and detects, as a contrast-evaluation-value maximizing optical-path length, an optical-path length of the second light beam corresponding to a maximum contrast evaluation value, and executes focus control over the optical system based on the contrast-evaluation-value maximizing optical-path length and outputs focus-state information indicating an in-focus state; and an imaging-purpose signal generation unit that generates a video signal for imaging-purpose using the first signal and the second signal when the focus-state information indicates an in-focus state, and generates a video signal for imaging-purpose using the first signal and without using the second signal when the focus-state information indicates an out-of-focus state.