A control apparatus includes: an acquisition unit that obtains a face image including a face area of an authentication target; a calculation unit that calculates information about luminance of each of a plurality of areas in the face area; and an output unit that outputs a control parameter for controlling a lighting unit that applies an illumination light when the face image is captured, on the basis of the information about the luminance. According to such a control apparatus, it is possible to output information required for an appropriate optical environment when the face image of the user is captured.