Another example where motor drivers are commonly found is in the video projector. Most mid-end projectors will have motor driven zoom and focus. In lower-end models, these functions are done manually. When the projector is mounted in a remote place, such as a high ceiling, it is convenient to be able to adjust the zoom and focus without having to get out a ladder. High-end models could include a motor for lens shift and an iris function. Lens shift is the ability to control the position of the lens in all directions. Some projectors have a swivel function, enabling the chassis to move right and left.