Canon's last Canonflex — the RM, R mount, built-in selenium meter, cloth shutter to 1/1000, 1962.
The Canonflex RM appeared in 1962 as the final and most refined member of Canon's first SLR family, still on the Canon R breech-lock mount. It was the first Canonflex to integrate a meter into the body, marking a step toward the metered SLRs that followed with the FL system.
This 35mm SLR used the Canon R breech-lock bayonet and a cloth focal-plane shutter running 1 second to 1/1000 with bulb. It carried a built-in selenium meter mounted on the front of the pentaprism housing, coupled to the shutter-speed dial, with exposure still set manually by the photographer. Being selenium-cell metering, it required no battery, and the mechanical shutter fired independently of any power source.
The RM suits users wanting an early Canon SLR that includes its own light meter without needing a clip-on accessory. The selenium meter and conventional advance lever make it more practical for everyday shooting than earlier Canonflex models, though its match-needle manual exposure keeps it a deliberate camera. It handles travel and general photography for those content with manual control.
When buying, test the built-in selenium meter against a known reference, as selenium cells weaken or die with age and the reading may be low. Check the cloth shutter for accuracy and capping across the range, inspect for perished light-seal foam, and look for prism desilvering or haze. Confirm smooth film advance and rewind. R-mount lenses adapt to mirrorless bodies for continued use.