A camera system 100 has an imaging optical system L, an imaging component 45, a liquid crystal monitor 16, a body microprocessor 12, an aperture setting component 29, and an image display controller 15. The body microprocessor 12 allows a target aperture value and a reference aperture value to be set as set conditions and determines the reference aperture value on the basis of the target aperture value. The aperture setting component 29 adjusts a photography condition on the basis of the set conditions. The image display controller 15 displays part of a reference image a1 acquired by the imaging component 45 at the reference aperture value as a reference display image A1 in a first display region R131 and displays part of a target image b1 acquired by the imaging component 45 at the target aperture value a1 as a target display image B1 in a second display region R132.