A positioning device disposes an optical component with respect to an optical axis. The positioning device has a lens carrier (14) for housing the lens (18) or other optical component, a mount (12) supporting the lens carrier along the optical axis, the lens carrier movable within the mount in at least one direction. An extended member is coupled to the lens carrier for setting the position of the carrier within the mount. A movable cam urges the extended member to effect movement in the at least one direction.