Canon FL Lenses
1 interactive lens diagram
Canon manual-focus SLR mount, 1964-1971 | 35 mm SLR
Canon FL replaced the original Canon R mount and became Canon's main 35 mm SLR interface through the mid-1960s. It kept the breech-lock mounting style and automatic diaphragm operation, but predated the full FD system coupling used for open-aperture metering.
FL lenses occupy a transitional place in Canon history. They include conventional standards and telephotos, early wide-angle SLR designs, and specialist lenses made while Canon was still refining its reflex camera identity against Nikon, Pentax, Minolta, and others.
Many FL lenses can be used on later FD bodies with stop-down metering, which makes the family optically connected to FD even though the camera-lens coupling is simpler. In the catalog, FL entries should read as Canon's mature pre-FD manual-focus engineering rather than as early EOS ancestry.
Mount interface
Flange focal distance 42 mm, breech_lock mount. 0° at 12 o'clock from the camera front; the lens-side view is the horizontal mirror. Dotted strokes mark photo-scaled or schematic (not-to-scale) dimensions.