Rotating Focusing Mechanism

A mechanical method of adjusting the focus of an optical assembly, such as an imaging lens or laser beam expander, in which optical components are rotated during translation. Rotating focusing mechanisms are simple and inexpensive, but they can suffer from image runout or beam wander due to the rotation of the elements. Sliding focusing mechanisms, which translate optical elements without rotation, reduce image runout and beam wander but are typically more expensive due to their more complicated mechanics. Threaded focusing tubes are a common type of rotating focusing mechanism.