An image capturing apparatus includes a setting unit for enabling a user to set control values, a display unit for displaying the control values, an obtaining unit for obtaining an aperture value of a lens unit based on luminous information of an object image and the control values set by the user, and a calculation unit for calculating a signal for controlling an aperture of the lens unit according to the aperture value, wherein when the aperture value of the lens unit is a first aperture value, a value based on the first aperture value is displayed and a signal corresponding to the first aperture value is calculated, and when the aperture value of the lens unit is a second aperture value, a value based on the second aperture value is displayed and a signal corresponding to a third aperture value which is different from the second aperture value is calculated.