Patent ID: 9288378
Filing Date: 2016-03-15
CPC Classification: G02B,G03B,H04N

Claim Text:
1. An autofocus apparatus comprising: a memory; and a lens controller, which includes a processor, configured to execute: a target position calculating task that calculates a target position of a focus lens based on a defocus amount obtained based on a signal from a focus detector of a phase difference detecting type and a position of the focus lens obtained by a position detector; a target position storing task that stores in the memory the calculated target position; an object speed calculating task that calculates an object speed in an optical axis direction based on a present target position, a target position calculated prior to calculating of the present target position, and one of a target position calculation time consumed from a time at which the target position calculating task calculates the target position calculated prior to calculating of the present target position to a time at which the target position calculating task calculates the present target position or a time regarded as equivalent to the target position calculation time; a first drive speed setting task that sets a drive speed of the focus lens based on the present target position, the position of the focus lens, and the object speed; a second drive speed setting task that sets the drive speed of the focus lens based on a present drive speed of the focus lens, a present defocus amount, and the defocus amount obtained prior to obtaining of the present defocus amount; an object speed change determining task that determines whether or not the object speed changes; a first driving task that drives the focus lens based on the drive speed set by the first drive speed setting task in a case where the object speed has been determined to change; and