Lens barrel for a camera having a non-rotatable cam ring moved by a feed screw

摘要

A varifocal mechanical correction mechanism for a lens barrel for a camera, wherein the mechanism drives a lens with a pair of cam rings for carrying out zooming and focusing functions. One of the cam rings is caused to linearly move in and out along an optical axis by a feed screw. The feed screw that has a shank portion outside a normal feed range and on a non-threaded portion of a shaft.