Ricoh GW-2 21mm Wide Conversion Lens with Hood for the GR Digital III Camera, Requires GH-2 Adapter for Mounting.

Wide Conversion Lens GW-2 expands the GR Digital III's field of view to 21mm...
The GW-2 21mm-Wide-Conversion Lens unit expands the angle of view to a super wide 21mm without compromising the camera's superb optical performance. (the GH-2 Adapter is required in order to be able to mount the GW-2 on the GR-III)

An electronic sensor in the GR III Digital detects when the GW-2 lens is mounted and adjusts autfocusing accordingly to insure focusing. A detachable hood is also included with this conversion lens for blocking unneeded light and preventing unintentional flares from spoilling wide-angle photos.