A camera system which is capable of performing highly accurate focusing in a
short
time by using two kinds of AF methods, is disclosed. The camera system calculates
the target driving amount of the focusing lens based on the result of detection
by a first focus detection unit, and performs a first driving control to drive
the focusing lens toward a position corresponding to the target driving amount
and a second driving control to drive the focusing lens based on the result of
detection by the second focus detection unit. When the remaining driving amount
to the target driving amount of the focusing lens by the first driving control
becomes a predetermined amount, the camera system switches from the first driving
control to the second driving control without stopping the focusing lens.