At a lens group position storage unit, the positions of a focus lens group and
a zoom lens group detected at the time of a preset operation are stored. In response
to an instruction for a go-home operation, a zoom lens group position comparison
unit compares the current zoom lens group position with the position detected at
the time of the preset operation. If the zoom lens group position assumed when
the instruction for the go-home operation is issued is further toward the telephoto
side relative to the zoom lens group position at the time of the preset operation,
a defocus prevention unit issues a warning so as to prevent defocusing.
