To improve convenience when confirming the depth of field.

A camera system 100 includes an imaging optical system L, an imaging section 45, an image recording section 18, a reflection mirror 4, a mirror driving section 44, an aperture value input section 40, a diaphragm adjusting section 29, a display section 16, an image adjusting section 59, and a preview operation section 76. In a focusing mode in which the reflection mirror 4 is operated in a second state of being withdrawn from an optical path, an aperture value of the imaging optical system L is adjusted to an inputted aperture value on the basis of a preview operation, and then the image adjusting section 59 adjusts an image displayed at the display section 16 darkened corresponding to the aperture value to be bright when increasing the aperture value.