A lens system according to a first aspect of the present invention includes an interchangeable lens, and an accessory which is mounted between the interchangeable lens and a camera body. The interchangeable lens is mountable to the camera body via the accessory and includes a lens-side communication unit that communicates with the camera body and the accessory, an accessory information acquisition unit that communicates with the accessory to acquire individual identification information of the accessory, an interchangeable lens information storage unit that stores individual identification information of the interchangeable lens, and an identification information generation unit that generates combination identification information which is information unique to a combination of the interchangeable lens and the accessory on the basis of the acquired individual identification information of the accessory and the stored individual identification information of the interchangeable lens, and the lens-side communication unit transmits the generated combination identification information to the camera body.