| 摘要 |
PURPOSE:To shorten the total measurement time by activating an automatic focus control means at an image pickup position when a distance is larger than a specific positive threshold value and inactivating said control means at the image pickup position when the distance is smaller than the threshold value. CONSTITUTION:Once an image pickup optical device 170 is automatically focused, focusing is not performed again when the device 170 moves relatively in a range of a distance equal to the threshold value from the image pickup position, i.e. an encircled range wherein the radius centering on the image pickup position is equal to the threshold value to take a measurement. Then when the device 170 moves relatively to an image pickup position outside the range surrounded with the circle, the automatic focusing is performed again at the image pickup position. Further, the automatic focusing is not performed at an image pickup position in a range surrounded with a circle having the radius equal to the threshold value centering on the image pickup position where the focusing is performed newly. |
