Image pickup apparatus with an optical filter used for in-focus determinations

An image pickup apparatus comprising:

• an image sensor configured to photoelectrically convert an object image formed by an optical system including a focus lens, and to generate an image pickup signal;
• an optical filter;
• an actuator configured to insert and to eject the optical filter into and from an optical path between the optical system and the image sensor;
• and
• at least one processor or circuit programmed to function as a controller configured to search for an in-focus position based on the image pickup signal and to control a position of the focus lens based on a result of a search,
• wherein the controller determines whether the focus lens is to move by a first amount after the optical filter moves from one of the position on the optical path and the position outside the optical path to the other, and before the search starts, based on a difference between an in-focus position when the optical filter is disposed on the optical path and an in-focus position when the optical filter is not disposed on the optical path, and
• wherein the controller searches for the in-focus position after moving the focus lens by the first amount when the difference is larger than a threshold, and searches for the in-focus position from a position of the focus lens before the optical filter is moved when the difference is smaller than the threshold.