| 摘要 |
PURPOSE:To prevent the deviation of magnification and focus due to the accumulation of the error of the extent of lens movement, by returning an optical member to a reference position when the elapse time from a prescribed time exceeds a prescribed value and counting the number of pulses from this position to move the optical member to a required position. CONSTITUTION:When it is judged that the movement of a lens 13 is necessary, the time of timer T2 and a preliminarily set time (t) are compared with each other; and if the time of the timer T2 exceeds the time (t), it is judged that the number of magnification changes is large, and the lens 13 is returned to a reference position 134 temporarily, and the lens 13 is moved from this position to a position designated by a magnification designating key. If the time of the timer T2 does not exceed the time (t), it is judged that the number of magnification changes is small, and it is discriminated that the accumulation of the error of the extent of lens movement is less without returning the lens 13 to the reference position, and the lens 13 is moved directly to a desired position. |
