An imaging area in an image sensor includes a plurality of photo detectors. A light shield is disposed over a portion of two photo detectors to partially block light incident on the two photo detectors. The two photo detectors and the light shield combine to form an asymmetrical pixel pair. The two photo detectors in the asymmetrical pixel pair can be two adjacent photo detectors. The light shield can be disposed over contiguous portions of the two adjacent photo detectors. A color filter array can be disposed over the plurality of photo detectors. The filter elements disposed over the two photo detectors can filter light representing the same color or different colors.