Focus detection device and focus detection method

摘要

The area in which focus detection is performed is selected from among a plurality of focus detection areas provided on a photography screen. In the pair of photoelectric converters corresponding to the selected focus detection area, charge accumulation is repeatedly performed based on at least one of the image signals from the pair of image signals output from this pair of photoelectric converters. The focus adjustment condition of the photograph optical system is computed based on this pair of image signals. In the pair of photoelectric converters corresponding to the non-selected focus detection areas, charge accumulation is repeatedly performed over a period longer than the period of charge accumulation in the pair of photoelectric converters corresponding to the selected focus detection area based on at least one of the image signals from the pair of image signals output from this pair of photoelectric converters. The structure and method improve the responsiveness of focus detection when the focus detection area is changed without causing the responsiveness of normal focus detection to decline.