When the camera optic system of the shield portion 218 is at least partially aligned with the camera 226 of the mobile device 202, as shown in FIG. 2, the combined lens system that is formed by the camera lens 228, the aperture 235, and the camera optic system lens 234 may be referred to herein as a barcode reading lens system. Similarly, when the illumination optic system of the shield portion 218 is at least partially aligned with the illumination source 232 of the mobile device 102, as shown in FIG. 2, the combined illumination system that is formed by the illumination source 232 and the illumination optic system lens 236 may be referred to herein as an exposure illumination system.

The camera optic system may be configured to modify the field of view 240 of the camera 226 of the mobile device 202 such that the field of view 238 of the barcode reading lens system is different from the field of view 240 of the camera 226 by itself. More specifically, the camera optic system lens 234 and the aperture 235 may be configured to modify the field of view of the camera lens 228 of the mobile device 202 such that the angular size of the field of view 238 of the barcode reading lens system is different from the angular size of the field of view 240 of the camera 226 by itself. For example, the angular size of the field of view 238 of the barcode reading lens system may be significantly smaller than the angular size of the field of view 240 of the camera 226 by itself. This is because the camera 226 may be designed for general purpose photography, which often uses a wider lens angle than is needed for capturing barcode images.