An electronic apparatus (100, 200), comprising: a processing unit (134, 131, 113, 114, 117) capable of setting one of a zoom adjustment position and a zoom numerical value; a display control unit (210, 203) to display a knob (341, 351, 361, 431, 441, 451) that is moved on a slider in accordance with a user operation as a setting screen of one of the zoom adjustment position and the zoom numerical value, and set a position of the knob as a default position on the slider, when the user operation is not performed, the default position being the centre of the slider; and an operation control unit to change one of the zoom adjustment position and the zoom numerical value depending on a change of the position of the knob by the user operation on the setting screen displayed by the control of the display control unit, the position of the knob being changed with the change of the user operation on the setting screen wherein the operation control unit stops changing one of the zoom adjustment position and the zoom numerical value immediately when a dragging operation on the knob is not performed by the user, the display control unit (210, 203) returns a display position of the knob to the default position at the centre of the slider by using a predetermined time period, when the dragging operation is not performed; characterised in that in accordance with an amount of shift of the knob from the default position, the operation control unit changes the speed at which the one of the zoom adjustment position and the zoom numerical value are changed, wherein the farther the knob is positioned from the default position, the faster the speed, and the nearer the knob is positioned from the default position, the slower the speed. a processing unit (134, 131, 113, 114, 117) capable of setting one of a zoom adjustment position and a zoom numerical value; a display control unit (210, 203) to display a knob (341, 351, 361, 431, 441, 451) that is moved on a slider in accordance with a user operation as a setting screen of one of the zoom adjustment position and the zoom numerical value, and set a position of the knob as a default position on the slider, when the user operation is not performed, the default position being the centre of the slider; and an operation control unit to change one of the zoom adjustment position and the zoom numerical value depending on a change of the position of the knob by the user operation on the setting screen displayed by the control of the display control unit, the position of the knob being changed with the change of the user operation on the setting screen wherein the operation control unit stops changing one of the zoom adjustment position and the zoom numerical value immediately when a dragging operation on the knob is not performed by the user, the display control unit (210, 203) returns a display position of the knob to the default position at the centre of the slider by using a predetermined time period, when the dragging operation is not performed; characterised in that in accordance with an amount of shift of the knob from the default position, the operation control unit changes the speed at which the one of the zoom adjustment position and the zoom numerical value are changed, wherein the farther the knob is positioned from the default position, the faster the speed, and the nearer the knob is positioned from the default position, the slower the speed.