1. An apparatus removing a moire pattern of a digital imaging device, the apparatus comprising: a moire pattern detecting unit which determines whether or not a moire pattern is generated, by comparing an image frequency of a preview image and a spatial frequency of an image sensor, wherein the spatial frequency is defined based on the inverse of a distance between pixels of the image sensor for obtaining the preview image; and an optical path adjusting unit which changes an optical path of light incident to the image sensor to perform low-pass filtering when it is determined by the moire detecting unit that a moire pattern is generated, wherein the optical path adjusting unit moves the optical path by a distance of at least one pixel while the image sensor is exposed to light under the control of the moire pattern detecting unit.