| 摘要 |
PURPOSE:To attain optimum focusing operation everytime by adjusting focus while balancing the stability and sensitive property of an automatic focusing system in accordance with the level of contrast. CONSTITUTION:The level of the contrast of a subject is appreciated and the moving distance of a focusing means is changed in accordance with the appreciation. When the contrast of the subject is low, a contrast deciding part 113 outputs a signal 114 for converting a focal shift on the basis of a contrast appreciating value signal 112 obtained from an arithmetic part 104, so that a lens group 10 is not moved to a false position until the shifted distance obtained from the arithmetic part 104 always shows a false large value, i.e. an incorrect distance generating overshoot is frequently generated. On the other hand, the contrast deciding part outputs a conversion factor signal close to '1' in accordance with the increase of the contrast and a comparison deciding part 108 increases its response capacity. Consequently, a motor driving circuit 110 repeats stable focusing operation on the basis of distance information, i.e. a shift distance signal 105. |
