Patent ID: 8754979

Claim:
A focus adjustment device comprising: a driver that drives a focus adjustment optical system to change a focus status of an optical system; a focus detector that detects evaluation values with respect to contrast of images by the optical system in a plurality of different focus statuses to perform focus detection for the optical system; an obtaining unit that obtains a maximum driving speed among speeds with which the focus adjustment optical system is able to be driven; and a controller that causes the driver to perform a first driving operation in which the focus adjustment optical system is driven within a certain range and with a certain speed or to perform a second driving operation which is different from the first driving operation, wherein: the controller compares the maximum driving speed and a first driving speed as a driving speed for the focus adjustment optical system during the first driving operation with each other when a peak of the evaluation values fails to be detected within the certain range as a result of performing the first driving operation, and determines based on obtained comparison result whether or not to cause the driver to perform the second driving operation subsequently to the first driving operation, and the controller causes the driver to perform the second driving operation subsequently to the first driving operation when a peak of the evaluation values fails to be detected within the certain range as a result of performing the first driving operation and when the maximum driving speed and the first driving speed satisfy a relationship: (the maximum driving speed)·k1≧(the first driving speed), wherein (0<k1≦1).