An imaging apparatus , comprising: a mount connectable to an optical system including a focus lens an image sensor configured to capture a subject image formed via the optical system, to generate image data; and a controller configured to control a focusing operation for adjusting a position of the focus lens along an optical axis in the optical system according to an evaluation value for a focus state, characterized in that in response to a user instruction to reduce or increase a distance to a subject to be focused in response to said focusing operation, the controller is operable to: shift a position of the focus lens by a shift width (W1,W2) from a current position (P0) of the focus lens toward a direction according to the user instruction in directions along the optical axis to a start position (P1), wherein the shift width (W1,W2) is set to a width larger than a presumed or predetermined peak width (W0) applied to detect a peak position (P10) nearest to the current position (P0), thus causing said peak position (P10) in the vicinity of the current position (P0) not to be detected, wherein the start position (P1) is a position of the focus lens for starting the focusing operation, and wherein the controller is operable to start the focusing operation from the start position (P1) after the shift. a mount connectable to an optical system including a focus lens an image sensor configured to capture a subject image formed via the optical system, to generate image data; and a controller configured to control a focusing operation for adjusting a position of the focus lens along an optical axis in the optical system according to an evaluation value for a focus state, characterized in that in response to a user instruction to reduce or increase a distance to a subject to be focused in response to said focusing operation, the controller is operable to: shift a position of the focus lens by a shift width (W1,W2) from a current position (P0) of the focus lens toward a direction according to the user instruction in directions along the optical axis to a start position (P1), wherein the shift width (W1,W2) is set to a width larger than a presumed or predetermined peak width (W0) applied to detect a peak position (P10) nearest to the current position (P0), thus causing said peak position (P10) in the vicinity of the current position (P0) not to be detected, wherein the start position (P1) is a position of the focus lens for starting the focusing operation, and wherein the controller is operable to start the focusing operation from the start position (P1) after the shift. shift a position of the focus lens by a shift width (W1,W2) from a current position (P0) of the focus lens toward a direction according to the user instruction in directions along the optical axis to a start position (P1), wherein the shift width (W1,W2) is set to a width larger than a presumed or predetermined peak width (W0) applied to detect a peak position (P10) nearest to the current position (P0), thus causing said peak position (P10) in the vicinity of the current position (P0) not to be detected, wherein the start position (P1) is a position of the focus lens for starting the focusing operation, and wherein the controller is operable to start the focusing operation from the start position (P1) after the shift. <EOS>