MULTISTAGE EXTENSION TYPE LENS BARREL

摘要

PROBLEM TO BE SOLVED: To provide a multistage extension type lens barrel which is easy to assemble and maintain while securing the rigidity on the whole without being made large-sized. SOLUTION: The multistage extension type lens barrel is equipped with a helicoids extension structure having an outer peripheral helicoids ring having a helicoids formed on the outer peripheral surface and an inner peripheral helicoids ring having a helicoids with which the mentioned helicoids threadably engages on the inner peripheral surface. The lens barrel is further equipped on the outer peripheral helicoids ring with: a straight-moving guide ring which is so supported as to freely move relative to the outer peripheral helicoids ring and move together along the optical axis; and an external cylinder which is formed independently of the outer peripheral helicoids ring, so fitted in the straight-moving guide ring to freely rotate relatively and move together along the optical axis, and attachably/detachably coupled with the outer peripheral helicoids ring to rotate and move along the optical axis together with the outer peripheral helicoid ring and cover the lens barrel.