A 3D imaging apparatus with enhanced depth of field to obtain electronic images of an object for use in generating a 3D digital model of the object. The apparatus includes a housing having mirrors positioned to receive an image from an object external to the housing and provide the image to an image sensor. The optical path between the object and the image sensor includes an aperture element having apertures for providing the image along multiple optical channels with a lens positioned within each of the optical channels. The apparatus also includes a transparent cover positioned within the optical path and having a plurality of fiducials. The depth of field of the apparatus includes the cover, allowing the fiducials to be used to calibrate the apparatus or verify and correct the existing calibration of it.