Ricoh's 35mm SLR system based on the original Pentax K mount. The most advanced cameras of the system - XR-2, XR-2S, KR-10, KR-10SE, XR6, XR-S, XR7, XR500 auto, XR-2000, XR-F - featured an electronically controlled shutter and aperture-priority auto exposure mode, while conventional models - XR-1, XR-1S, XR500, XR5 - had a mechanical shutter and offered manual exposure mode only. The XR-8, XR-8 Super, XR Solar, and KR-5SV, conventional models introduced in the 1990s, were designed and manufactured by Cosina.
In order to implement shutter priority and programmed auto exposure modes, Ricoh modified the original Pentax K mount and introduced a separate line of cameras and Rikenon P lenses in 1984.
An unusual feature of the Ricoh K system was a large selection of standard lenses: from several versions of budget models with moderate speeds of F/2.2, F/2 and F/1.7 to professional models with speeds of F/1.4 and even F/1.2. As for the accessory lenses, they were produced in collaboration with companies such as Asahi, Sigma, and others.
RICOH XR TELE CONVERTER 2X was available for XR Rikenon lenses. Unfortunately, we do not have the manufacturer specification for this teleconverter and information about its compatibility with XR Rikenon lenses.