An image capture apparatus comprising: an image sensor configured to capture a subject image, formed by an imaging optical system having a focus lens and a diaphragm, and to output an image signal; manual focus operation means configured to enable setting of a focus lens position based on an instruction from a user; and calculation means configured to calculate an in-focus level of the imaging optical system based on the image signal acquired after setting the focus lens position; characterized by control means configured: to determine a diaphragm driving direction and a diaphragm driving amount being calculated such that it is proportional to a difference between the in-focus level and a threshold; to determine a moving direction of the focus lens based on an output signal of the image sensor, and to determine a driving amount of the focus lens corresponding to an expected change amount of depth of field if the diaphragm is driven based on the determined diaphragm driving amount, wherein the diaphragm is driven according to the determined diaphragm driving direction and the determined diaphragm driving amount, and the focus lens is driven according to the determined focus lens moving direction and the determined focus lens driving amount in order to ensure that depth of field includes a focus position corresponding to the focus lens position set by the user. an image sensor configured to capture a subject image, formed by an imaging optical system having a focus lens and a diaphragm, and to output an image signal; manual focus operation means configured to enable setting of a focus lens position based on an instruction from a user; and calculation means configured to calculate an in-focus level of the imaging optical system based on the image signal acquired after setting the focus lens position; characterized by control means configured: to determine a diaphragm driving direction and a diaphragm driving amount being calculated such that it is proportional to a difference between the in-focus level and a threshold; to determine a moving direction of the focus lens based on an output signal of the image sensor, and to determine a driving amount of the focus lens corresponding to an expected change amount of depth of field if the diaphragm is driven based on the determined diaphragm driving amount, wherein the diaphragm is driven according to the determined diaphragm driving direction and the determined diaphragm driving amount, and the focus lens is driven according to the determined focus lens moving direction and the determined focus lens driving amount in order to ensure that depth of field includes a focus position corresponding to the focus lens position set by the user. to determine a diaphragm driving direction and a diaphragm driving amount being calculated such that it is proportional to a difference between the in-focus level and a threshold; to determine a moving direction of the focus lens based on an output signal of the image sensor, and to determine a driving amount of the focus lens corresponding to an expected change amount of depth of field if the diaphragm is driven based on the determined diaphragm driving amount, wherein the diaphragm is driven according to the determined diaphragm driving direction and the determined diaphragm driving amount, and the focus lens is driven according to the determined focus lens moving direction and the determined focus lens driving amount in order to ensure that depth of field includes a focus position corresponding to the focus lens position set by the user.