1. A control apparatus for controlling a driver driving an optical element of an image pickup device to adjust a focus position of the image pickup device in the capturing of an image of a subject, the control apparatus comprising: local peak comparing means for comparing a local peak of an assessment value, as a parameter for adjusting the focus position, with a local peak of an integrated luminance value, the assessment value assessing an out-of-focus level of the captured image of the subject on a per field image basis, the integrated luminance value being obtained by integrating a luminance value of the captured image of the subject on a per field image basis, and the local peak comparing means compares the local peak of the assessment value with the local peak of the integrated luminance value in terms of peak position and peak count; and mode selecting means for selecting, from among a plurality of prepared modes, a mode searching for a peak over the entire range of the assessment value based on the comparison result provided by the local peak comparing means.