An imaging device controller that controls an imaging device, comprising a detector and a driver, is provided. The imaging device is mounted in an image capturing apparatus. The image capturing apparatus has plural functions. The detector detects that the first function among the functions is carried out. The driver orders the imaging device to capture an optical image in a first interval before or after a detection period. The detector is detecting that the first function is carried out during the detection period. The driver orders the imaging device to capture an optical image in a second interval during the detected-period. The second interval is longer than the first interval.