Ricoh today announced the GXR, an interchangeable lens camera that is unlike anything else currently on the market. The GXR is what Ricoh calls an interchangeable unit camera system. It doesn't have a built-in sensor. Instead, the lenses you use will have a built-in sensor that best matches the lens capability. This is the 'unit' that Ricoh refers to and it has allowed Ricoh to create what it claims is the world's smallest interchangeable lens camera.