An imaging system of the present invention comprises a lens unit having a barrel section that contains a photographing optical system, and an operating section provided on the barrel section, and a camera body having an imaging section for converting a subject image formed by the photographing optical system into electrical signals, and a display section for displaying the subject image based on the electrical signals, wherein the lens unit has a transmission section for transmitting information relating to the operation section, and the camera body has a receiving section for receiving information relating to the operating section that has been transmitted from the transmission section, and an association section for displaying the information relating to the operation section that has been received by the receiving section on the display section, and associating information relating to the operating section with functions of the camera body.