| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical instrument capable of performing AF with high speed and high accuracy in the case of using two types of focus detection methods and including two driving means and two focus lens groups. <P>SOLUTION: In a phase different AF mode, if a driving amount of a second stepping motor 19 is greater than a first threshold value, a first lens group 11 is driven by a first stepping motor 18, and if a driving amount of the second stepping motor 19 is equal to or less than the first threshold value, a second lens group 13 is driven by the second stepping motor 19. In a contrast AF mode, if driving velocity of the second stepping motor 19 calculated from the driving amount and driving time of the second stepping morot 19 is greater than a second threshold value, the first lens group 11 is driven by the first stepping motor 18, and if the driving velocity of the second stepping motor 19 is equal to or less than the second threshold value, the second lens group 13 is driven by the second stepping motor 19. <P>COPYRIGHT: (C)2013,JPO&INPIT |
