Wide Conversion Lens GW-1 expands the GR Digital & GR Digital II's field of view to 21mm... The GW-1 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-1 Adapter is required in order to be able to mount the GW-1 on the GR) An electronic sensor in the GR Digital detects when the GW-1 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.