In an imaging apparatus that includes a lens unit and a body unit, when a diaphragm value of a variable diaphragm is changed, the lens unit calculates an announcement value indicating the diaphragm value when a prescribed time period has passed since a detection time of a current diaphragm value of the variable diaphragm, and transmits the announcement value to the body unit, and the body unit controls exposure of an image sensor on the basis of the announcement value obtained from the lens unit.