| 摘要 |
PURPOSE:To make it unnecessary to increase the capacity of a memory by using a simple polynomial expression determined by characteristic values of an optical system to stop a zoom lens by extension of the length between minimum and maximum magnifications or increase of the number of magnification steps. CONSTITUTION:A console 1 consists of a fixed magnification input key 10 and an optional magnification input key 11, and a detection signal 9A from an unmagnification detector 9, a signal 10A from the fixed magnification input key 10, and a signal 11A from the optional magnification input key 11 are inputted to a control circuit 2. A driving signal 13A which rotates a pulse motor 3 is outputted by signal 12A and 12B from a CPU12. A processing circuit 13, which transmits the position of the zoom lens as an oscillated frequency signal 13B, and a memory 14 are included. A number F of pulses corresponding to a magnification is obtained with a function of an input magnification M in accordance with a polynomial expression 6, and the CPU12 performs this operation to determine the rotation direction of the pulse motor 3 and the number of pulses of movement. |
