Patent ID: 8872962

Claim:
A focus detection apparatus comprising: an image pickup part configured to include (a) first pixels photoelectrically converting a first image formed by a light flux passing through a first pupil area of an image-forming optical system to produce a first image signal and (b) second pixels photoelectrically converting a second image formed by a light flux passing through a second pupil area of the image-forming optical system to produce a second image signal; a first signal processor configured to perform a first process to smooth the first and second image signals by using mutually different filters for the first and second image signals; a second signal processor configured to perform a second process to sharpen the first and second image signals by using mutually different filters for the first and second image signals; and a calculating part configured to calculate a defocus amount of the image-forming optical system by using the first and second image signals on which the first process or the second process has been performed, wherein the calculating part is configured to calculate the defocus amount by using the first and second image signals on which the first process has been performed when a contrast value obtained from an output signal from the image pickup part is higher than a predetermined value, and calculate the defocus amount by using the first and second image signals on which the second process has been performed when the contrast value is lower than the predetermined value.