Patent ID: 7570879

Claim:
An image sensing apparatus which can exchange a lens unit which includes a control unit for determining a driving direction in which a focus lens of an optical system is driven to a focused focal point and determining a driving speed on the basis of an increase/decrease in level of a sign of an AF evaluate value output from said image sensing apparatus and a driving unit for driving the focusing lens on the basis of the determination of said control unit, said apparatus comprising: an extraction unit configured to extract one or a plurality of focus signals in one or a plurality of focus detection areas within a frame from an image sensing signal output from an image sensing unit; and a transmitting unit configured to transmit to said lens unit said signals extracted by said extraction unit, as the AF evaluate value; wherein an extraction characteristic of said extraction unit is changed in accordance with a type of said lens unit, and wherein when the focusing lens is driven in one direction to change a focusing state from a blurring state to a blurring state through a focused state, the extraction characteristic of said extraction means is changed, in an increasing/decreasing curve shape plotted by a focus signal level which changes in accordance with a focusing state, so as to change a sharpness of the increasing/decreasing curve shape.