Name Manufacturer / Model	Mount Bayonet	Type Category	Year Released	Focal mm	Aperture f/	Weight g
RicohXR Rikenon 50mm F/1.4	PENTAX K	Portrait	1977	50mm	f/1.4	260g
RicohXR Rikenon 50mm F/1.7	PENTAX K	Portrait	1977	50mm	f/1.7	210g
RicohXR Rikenon 50mm F/1.7 [I]	PENTAX K	Portrait	1977	50mm	f/1.7	210g
RicohXR Rikenon 50mm F/1.7 [II]	PENTAX K	Portrait	1981	50mm	f/1.7	153g
RicohXR Rikenon 50mm F/2	PENTAX K	Portrait	1977	50mm	f/2	190g
RicohXR Rikenon 50mm F/2 L	PENTAX K	Portrait	1980	50mm	f/2	170g
RicohXR Rikenon 50mm F/2 S	PENTAX K	Portrait	1981	50mm	f/2	140g
RicohXR Rikenon 55mm F/1.2	PENTAX K	Portrait	1996	55mm	f/1.2	312g
RicohXR Rikenon 55mm F/1.7	PENTAX K	Portrait	—	55mm	f/1.7	150g
RicohXR Rikenon 55mm F/2.2	PENTAX K	Prime	1980	55mm	f/2.2	140g
RicohXR Rikenon 70-150mm F/3.5 Macro	PENTAX K	Macro	1977	70-150mm	f/3.5	735g
RicohXR Rikenon 70-150mm F/4 Macro	PENTAX K	Macro	1981	70-150mm	f/4	465g
RicohXR Rikenon Reflex 600mm F/8	PENTAX K	Mirror	1982	600mm	f/8	751g
Risespray50mm F/1.7 SLR	CANON EF	Portrait	—	50mm	f/1.7	180g
Risespray8mm F/3 Fisheye CS SLR	CANON EF	Fisheye	—	8mm	f/3	428g
RodenstockROTELAR 100mm F/4	M42	Telephoto	1956	100mm	f/4	—
RodenstockROTELAR 135mm F/4	M42	Telephoto	1956	135mm	f/4	—
RodenstockTIEFENBILDNER 120mm F/4.5 "IMAGON"	M42+ EXAKTA	Telephoto	—	120mm	f/4.5	—
RodenstockTIEFENBILDNER 120mm F/4.5 "IMAGON" [A]	M42+ EXAKTA	Telephoto	—	120mm	f/4.5	—
RodenstockYRONAR 135mm F/3.5	M42	Telephoto	1954	135mm	f/3.5	—
Rodenstock-Eurygon 30mm F/2.8	M42+ EXAKTA	Wide	1956	30mm	f/2.8	305g
Rodenstock-Heligon 50mm F/1.9	M42	Portrait	1956	50mm	f/1.9	—
Rodenstock-Rotelar 180mm F/4.5	M42	Telephoto	1956	180mm	f/4.5	—
Rodenstock-Yronar 135mm F/3.5 A	M42	Telephoto	—	135mm	f/3.5	—
Rollei-HFT PCS-Rolleigon 75mm F/4.5	ROLLEI SL66	Prime	1984	75mm	f/4.5	1313g
Rubinar1000mm F/10 Mirror MC Macro	M42+ PENTAX K	Mirror	—	1000mm	f/10	2300g
Rubinar300mm F/4.5 Mirror MC Macro	M42+ PENTAX K	Mirror	—	300mm	f/4.5	700g
Rubinar500mm F/5.6 Mirror MC Macro	M42+ PENTAX K	Mirror	—	500mm	f/5.6	1600g