Canon - f/3.5 200mm manual telephoto prime for FL breech-lock SLR bodies, also mounts on FD
Canon FL 200mm f/3.5 was a manual-focus telephoto prime for Canon's FL breech-lock SLR mount, which arrived in April 1964 with the Canon FX and went on to serve the FP, Pellix, FT QL and TL bodies before the FD mount replaced it in 1971.
The optical formula used 7 elements in 5 groups, with an aperture range from f/3.5 to f/22, a 2.5 metre minimum focusing distance and a 58mm filter thread. The barrel measured roughly 68mm in diameter by 152.5mm long. An earlier version weighed about 660 grams and a later revision about 680 grams, with identical optics.
FL lenses meter stop-down rather than at full aperture, so on a period body the finder darkens as the aperture ring is turned. The breech-lock collar seats the lens without rotating the barrel, which spares the mount surfaces and keeps any filter's alignment fixed. On later FD bodies the lens still mounts and works, again in stop-down mode.
UK used examples surface regularly and inexpensively, usually from dealers who file FL glass alongside FD stock. Buyers should check the diaphragm blades for oil, run the long focus helicoid through its full travel for stiffness or grit, and inspect the front element for cleaning marks and coating haze.