A camera system, comprising an imaging apparatus comprising a lens device and an imaging element; and a distance detection device, wherein the distance detection device comprises: a light emitting means configured to irradiate a target region with irradiation light; a light receiving means configured to receive reflected light of the irradiation light from a target in the target region; an acquisition means configured to acquire distance information indicating a distance to the target on the basis of a time until the light receiving means receives the reflected light after the light emitting means performs irradiation with the irradiation light; and a communication means configured to communicate the distance information, wherein the distance detection device is attached to the lens device at a position at which it surrounds the lens device, characterized in that the lens device is configured to store position information indicating the position of the distance detection device; the imaging apparatus is provided with a control means that acquires distance information indicating a distance between the distance detection device and the imaging element based on the position information stored by the lens device, and corrects a distance between the target and the imaging element obtained by the detection device based on the distance between the distance detection device and the imaging element. an imaging apparatus comprising a lens device and an imaging element; and a distance detection device, wherein the distance detection device comprises: a light emitting means configured to irradiate a target region with irradiation light; a light receiving means configured to receive reflected light of the irradiation light from a target in the target region; an acquisition means configured to acquire distance information indicating a distance to the target on the basis of a time until the light receiving means receives the reflected light after the light emitting means performs irradiation with the irradiation light; and a communication means configured to communicate the distance information, wherein the distance detection device is attached to the lens device at a position at which it surrounds the lens device, characterized in that the lens device is configured to store position information indicating the position of the distance detection device; the imaging apparatus is provided with a control means that acquires distance information indicating a distance between the distance detection device and the imaging element based on the position information stored by the lens device, and corrects a distance between the target and the imaging element obtained by the detection device based on the distance between the distance detection device and the imaging element. a light emitting means configured to irradiate a target region with irradiation light; a light receiving means configured to receive reflected light of the irradiation light from a target in the target region; an acquisition means configured to acquire distance information indicating a distance to the target on the basis of a time until the light receiving means receives the reflected light after the light emitting means performs irradiation with the irradiation light; and a communication means configured to communicate the distance information, wherein the distance detection device is attached to the lens device at a position at which it surrounds the lens device, characterized in that the lens device is configured to store position information indicating the position of the distance detection device; the imaging apparatus is provided with a control means that acquires distance information indicating a distance between the distance detection device and the imaging element based on the position information stored by the lens device, and corrects a distance between the target and the imaging element obtained by the detection device based on the distance between the distance detection device and the imaging element.