| 摘要 |
PURPOSE:To attain stable focusing without malfunction due to camera movement by clearing a memory content to restart the focusing when a fact that a difference between a focus evaluated value and the content of a maximum value memory reaches a prescribed value is detected. CONSTITUTION:When a camera itself and an object are standstill, a focus ring 2 is restored to a position where the focus evaluation value is maximized, the evaluated value at that point of time and the content of the maximum value memory 10 are equal to each other and a comparison signal from a comparator 14 keeps a L level. However, if an excessive vibration takes place due to camera movement or rapid movement of the object and the maximum value stored previously does not represent the true apex, even when the ring 2 is restored to the home position, the evaluated value is not equal to the content of the memory 10 and the comparison output keeps a H level. When the ring 2 is reversed into stop and the comparison output keeps the H level, the memory 10 and an initial value memory 11 are cleared and the automatic focusing is retried from the beginning. When the output is at the L level, the operation is finished. The stable focusing is attained by applying reconfirmation of the maximum point at the reverse stop time in this way. |
