A delay locked loop is used in a semiconductor memory device. A low opening region in which an aperture ratio of the holes per unit area is low and a high opening region in which an aperture ratio of the holes per unit area is high are formed in the filter. Additional apparatus, systems, and methods are disclosed. The focusing judge determines whether or not the distance-measuring area is a focus-adjustable area for which the focus adjuster can adjust a focus, based on the area subject distance.