| 摘要 |
PURPOSE:To correct a focusing signal and to perform correct automatic focusing even when an extender is inserted, by providing the expander with a signal generating circuit which corrects the focusing extent of a master lens according to the magnification of the extender. CONSTITUTION:The extender E is provided with the signal generating means which generates a signal corresponding to the magnification of the extender and the means is connected to a driving signal generation part 3. When the extender E has X magnifications, the focusing driving extent of the lens is only increased by 1/X<2> time, but a signal with a function f(X) is outputted so that the response of a motor 5 is considered. The dividing circuit of the driving signal generation part 3 divides driving time DELTAt for focusing from an image sensor IS by said f(X) to output DELTAt/f(X) as a driving signal, thereby controlling the master lens L in a specific direction. Therefore, even when the extender E is interposed, the focusing signal is corrected to perform correct automatic focusing. |
