An optical apparatus which achieves fast focusing operation and allows
accurate focusing is disclosed. The optical apparatus includes a first
focus detector which detects a focus state on a subject, a second focus
detector which detects a focus state on the subject in a detection method
different from a detection method of the first focus detector, and a
controller which has a function of detecting whether or not the subject
is a moving body and a function of performing focus control of an
image-taking optical system in a first sequence in which at least one of
the first and second focus detectors is used and a second sequence in
which at least the other of the focus detectors is used. The controller
preferentially uses one of the first and second sequences depending on
the result of the detection with the moving body detecting function.