| 摘要 |
PURPOSE:To device a lens drive direction accurately by deciding restarting of automatic focus adjustment from a decrease in a focus point and a change in a current focus voltage base on a signal in response to a focal state. CONSTITUTION:This image pickup device is provided with a 1st fixed lens group 101, a 2nd magnification lens group (zoom lens) 102, an iris 103, and a 3rd fixed lens group 104. The automatic focus is adjusted by moving a focus lens 105 so as to maximize the output signal level of a band pass filter 117. In this case, when the output signal level of the band pass filter 117 is decreased from a prescribed level over a prescribed time after focusing, it is judged that an object is moved and the focus lens 105 is moved again. The focus lens 105 is moved (wobbling) in the forward backward directions in his restarting and a change in the output signal level of the band pass filter 117 is observed to drive the lens in a direction at which the focal voltage is increased. |
