Ricoh GT-1 40mm Wide Conversion Lens for GR Digital & GR Digital II Cameras, Requires GH-1 Adapter for Mounting.

Tele Conversion Lens GT-1 extends the GR Digital & GR Digital II's focal length to 40mm. This focal length is good for effects as framing nearby subject and to obtain a natural perspective, also making it ideal for portraits and other shots. d ...
(the GH-1 Adapter is required in order to be able to mount the GT-1 on the GR)

An electronic sensor in the GR Digital detects when the GT-1 lens is mounted and adjusts autofocusing accordingly to insure focusing.