Autofocus device and method

摘要

Autofocus device has a lens-driving unit that drives a lens and a focal-point-position-detecting unit that detects a position of a focal point of the lens. The device also has a distance-measuring sensor that measures a distance to a subject and a control unit that performs a focusing operation to control the lens-driving unit to drive the lens, thereby meeting the position of the focal point of the lens detected by the focal-point-position-detecting unit to an in-focus position thereof. The control unit allows to be set a driving direction of the lens and a driving speed of the lens based on the position of the focal point of the lens detected by the focal-point-position-detecting unit and a distance measurement result measured by the distance-measuring sensor. The focusing operation then starts.