AUTOMATIC FOCUS ADJUSTING DEVICE

摘要

PURPOSE:To perform automatic focus adjusting operation with invariably high precision according to a subject by varying the number of decision circuits which decide on focusing or defocusing according to the contrast of the subject. CONSTITUTION:An analog signal 101 from a photodetecting element array is converted by an A/D converter 24 into a digital data group and an arithmetic processing part 113 calculates the evaluated value of contrast and its deviation quantity. A conversion part 113 sends out an output 114 corresponding to the frequency of defocusing decision as a function of a contrast evaluated value according to the evaluated value. Then, a comparison and decision part 108 compares the counted value of defocusing information on a counter 106 with the signal 114 corresponding to the frequency of defocusing decision, and generates a driving signal 109 according to information on the defocusing direction counted by the counter 106 for the 1st time when the counted value is equal to or larger than the frequency of defocusing decision.