AUTOMATIC FOCUSING DEVICE, LENS DEVICE HAVING THE SAME, AND IMAGING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a lens device having an automatic focusing function enabling a smooth focusing operation without a sense of incongruity irrespective of a lens photographic environment.SOLUTION: An automatic focusing device includes: an optical system including a focus lens; focus detection means for detecting a focusing state of the optical system with a phase difference detection method; defocus amount calculation means for calculating a defocus amount on the basis of a phase difference obtained by the focus detection means; driving amount calculation means for calculating a driving amount of the focus lens on the basis of the defocus amount calculated by the defocus amount calculation means; and control means for controlling drive of the focus lens. The control means controls a driving speed of the focus lens so that the driving amount calculated by the driving amount calculation means is driven in an electric charge accumulation time required for the focus detection means to detect a focusing state.