A camera system has an imaging optical system, an imaging component, a liquid crystal monitor, an aperture setting component, and an image display controller. The liquid crystal monitor has a first display region and a second display region. The aperture setting component adjusts the aperture in a specific period so that the actual aperture value will be a preset value. The image display controller displays, in the first display region, a reference image acquired by the imaging component under conditions in which the aperture value is the preset value, and displays, in the second display region, a comparative image acquired by the imaging component at a different timing from that of the reference image.