An optical navigation subsystem may be used when obtaining a candidate fingerprint for a mobile communication device (e.g., for authentication purposes). To accommodate such use of the optical navigation subsystem, the optical navigation subsystem may be adapted to automatically adjust a processed image sensor window from a first set of window dimensions (e.g., suitable for optical navigation) to a second set of window dimensions (e.g., suitable for fingerprint capture). Alternatively, a single, static set of window dimension may be employed in conjunction with stitching algorithms, or other methods suitable for forming candidate fingerprint images by combining a plurality of images obtained using the static set of window dimension.