| 摘要 |
PROBLEM TO BE SOLVED: To solve the following problem: regarding contrast AF system focusing, if a backlash amount is fluctuated due to the attitude or the tilt of a camera when a lens is reversely driven, compensation accuracy is deteriorated only by the addition of a fixed value, consequently, it is impossible to completely correct the backlash. SOLUTION: Regarding the contrast AF system focusing in the case of a lens barrel 110 with no built-in AF driving motor 130, a value obtained by multiplying the maximum value(peak) Pmax of a calculated focus estimation value by a prescribed value p(p<1) is set as a thresholdα. When a focus lens 120b is driven up to a calculated focus lens position LEmax, a focus estimation value is calculated again, and whether or not the focus estimation value is exceeding the thresholdαis judged, and the drive of the focus lens 120b and the calculation of the focus estimation value are continued until the focus estimation value exceeds the thresholdα. The driving amount of the focus lens 120b after reaching the calculated focus lens position LEmax is made smaller than the driving amount before the lens is reversely driven. COPYRIGHT: (C)2008,JPO&INPIT |
