Multiple sets of pixel values representing a captured image of a scene are received, with each set representing an image captured with a corresponding degree of focus. An image processor may identify a region of interest in the captured image, automatically determine the configuration parameters for a lens assembly to provide a desired degree of focus for the region of interest, and generate signals to configure a lens assembly. In an embodiment, the region of interest is a face, the desired degree of focus of the face is determined by computing a rate of variation of luminance of pixels representing the face, and the desired degree is the degree of the image having the maximum degree of focus.