An adapter suitable for use with digital cameras (and other digital imaging devices) converts the digital camera to a biometric scanner. One exemplary adapter includes a receptacle for receiving a body part, a coupler for attachment to the digital camera, and one or more optical components for acquiring an image of a biometric characteristic of the body part. Optional features might include: (a) automatically detecting of the body part and transmitting a command to an input interface of the camera; (b) using auxiliary lighting to illuminate the biometric image; (b) digitally post-processing the image after acquisition but prior to authentication; and/or (d) acquiring a biometric utterance of the user providing the biometric image for dual-factor biometric authentication; and/or still other features described herein.