1. A digital photographing apparatus comprising: an image pickup device which generates data from incident light; a mask preparer which prepares a mask having the same size as a reference image that is smaller than a current frame image, the mask to be applied to the current frame image to search for a target image that matches the reference image in the current frame image; a matching data obtainer which obtains a plurality of pieces of matching data by applying the mask to a plurality of matching images having the same size as the reference image, the plurality of matching images being parts of the current frame image; and a target image determiner which determines one of the matching images as a target image by using the matching data, wherein the mask preparer prepares at least one of: a color mask which, when applied to one matching image of the current frame image, gives a weight W c (i,j) to an (i,j) pixel of the one matching image according to a difference between a color data value of a corresponding pixel of the reference image and an average color data value of the reference image; a difference mask which, when applied to one matching image of the current frame image, gives a weight W D (i,j) to an (i,j) pixel of the one matching image according to a difference between a data value of a corresponding pixel of the reference image and a data value of a corresponding pixel of a target image in a previous frame image; and a resize mask which, when applied to one matching image of the current frame image, gives a weight W R (i,j) to an (i,j) pixel, by giving a weight of 1 to pixels of the one matching image corresponding to a rectangular area and giving a weight less than 1 to other pixels of the one matching image, wherein the rectangular area is selected among a plurality of rectangular areas concentric with the reference image, the reference image and a target image in a previous frame image showing highest accordance in the rectangular area among the plurality of rectangular areas when the reference image and the target image in the previous frame image area matched to be concentric.