PURPOSE: To confirm the depth of field in close-up photography by switching an operation member which associates automatic stop mechanisms of a camera body and a lens barrel with each other between the 1st and the 2nd states, and stopping down even the lens of a camera which has no stopping-down function.

CONSTITUTION: Stop-down interlocking pins 5, 6, and 7 which project inward in the close-up extension ring 1 are provided integrally to a changeover operation ring 2 fitted onto the outer periphery of the main body 1. The close-up extension ring body 1 and lens barrel are mounted on the single-lens reflex camera, and when the lens is stopped down manually from the state of normal use in which the stop of the lens is associated with the automatic stop mechanism, the counterclockwise rotation of the changeover operation ring 2 reset the interlocking between the automatic stop mechanisms of the camera and lens to allow the stop ring of the lens side to be varied optionally by manual operation, and the clockwise rotation of the changeover operation ring 2 places the camera in the normal use state.