Tv lens system and apparatus and method for zoom control

Abstract

A CPU of a lens system obtains contents of a speed control and a position control as a controller signal from a zoom controller. The speed control is based on an operation of a thumb ring which is instructed in a zoom controller, and the position control is based on a shot function or a limit function. These controls and a control based on a view angle correction function are executed by a process of the CPU, which follows a pre-set determination process; whereby, for example, an angle correction that was impossible to perform in a conventional art can be done after moving a zoom lens to a shot position based on the shot function. In a case that a rate control signal of the zoom lens that is provided from the zoom controller indicates stopping, the CPU fixes a position signal of the zoom lens that is outputted to the zoom controller to a position signal indicating a stopping position. In a case that a focus lens is moved by a focus controller, the zoom lens is moved to a position to prevent change of the view angle. Therefore, even if the zoom lens is stopped at the shot position, the zoom lens can be controlled based on the view angle correction function. Moreover, a limit position is detected in a predetermined direction and the view angle is corrected in consideration of the limit position; thus the zoom lens can be prevented from moving to the outside of the limit position by the view angle correction.