The A12 50mm F2.5 Macro is a lens unit that slides into Ricoh's GXR body. The GXR system takes a novel approach by offering interchangeable slide mount 'lens units' - sealed modules containing both optics and sensor, meaning it can switch from a large (APS-C) sensor with a fast prime lens to a tiny one (as in compact cameras) with zoom lenses. The Ricoh GXR/A12 50mm F2.5 Macro combines a 12MP APS-C sensor with a 50mm macro lens. This package offers very good image quality, robust build quality and a flexible user interface which make it a very interesting option for those who want (semi-) professional image output and handling in a very portable package. The camera's only real negative is its sometimes slow and/or unreliable contrast detect AF.