disclosed is a method of acquiring an image of a target to provide an output video image that has a plurality of frame images . the method includes the steps of receiving a series of frame images from a video camera , using a processor to manipulate the series of frame images , which includes determining a reference resolution for providing output frame images , and displaying and / or storing the manipulated series of frame images as the output video image without changing a resolution of the output frame images . also disclosed is a document imaging apparatus that includes a digital imaging unit . the digital imaging unit contains optics that having an infinite focal length . the document imaging apparatus also includes a processor that is coupled to the digital imaging unit and that is configured to cause the digital imaging unit to zoom in or zoom out in real - time while maintaining a resolution value of stored images constant . a non - transitory storage medium stores images obtained from the digital imaging unit and a display displays the stored images . a folding suspension arm supports the digital imaging unit at a distance from a target to be imaged .