An object of this invention is to provide an autofocus apparatus and method,
and
an image sensing apparatus capable of shortening the AF time without decreasing
the AF precision even when the total number of acquired AF evaluation signals is
large. To achieve this object, whether previous and current photographing conditions
satisfy a predetermined requirement in photographing is determined. When the previous
and current photographing conditions are determined to satisfy the predetermined
requirement, a focusing state only near an in-focus position in previous photographing
is detected. When the previous and current photographing conditions are determined
not to satisfy the predetermined requirement, a focusing state in the object region
is detected. An in-focus position is determined by detecting the focusing state,
and the in-focus position and photographing conditions are stored for the next
photographing. A focus lens is moved to the in-focus position to photograph.
