Adjustable lens mounting assembly

摘要

A lens barrel (10) is mated with a lens mount (12) by means of a screw thread (18) whereby relative rotation adjusts the lens focus. The lens barrel (10) and lens mount (12) are additionally provided with an interengaging formation (22) interposed between the optical axis and the screw thread (18). The formation (22) provides a cylindrical sliding contact which isolates any particles produced by operation of the screw thread (18) from reaching the optical components.