In a digital camera system, a lens barrel adapted to a first camera body can be attached to a second camera body having a flange focal length which is shorter than that of the first camera body via an intermediate adapter, and the intermediate adapter is interposed to thereby set the flange focal length to be equal. Moreover, a compensating optical device is incorporated in the intermediate adapter to thereby match an optical distance from a mount surface to an image capture surface of the first camera body with an optical distance from a mount surface of the intermediate adapter to an image capture surface of the second camera body in a state in which the intermediate adapter is attached.