Sigma's vintage fast telephoto zoom for Canon FD — the 80-200mm f/3.5 with constant aperture.
The Sigma 80-200mm f/3.5 is a vintage telephoto zoom from Sigma produced for the Canon FD mount in the 1970s–1980s. The Canon FD mount was the standard bayonet for Canon's film SLR range until it was superseded by the EF mount in 1987. FD lenses cannot be adapted to Canon EF or RF bodies without optical adapters.
The lens covers 80–200mm with an f/3.5 constant maximum aperture, manual focus with Canon FD bayonet coupling, fully manual aperture operation via the aperture ring, and full-frame 35mm coverage. The constant f/3.5 is faster than most consumer telephoto zooms of the era.
The Canon FD mount is popular for adapted use on mirrorless cameras — Sony E, Micro Four Thirds, Fujifilm X, and Canon RF systems all have adapters available that preserve infinity focus with FD-mount lenses. The constant f/3.5 maximum aperture is a useful specification for available-light telephoto work when adapted to modern mirrorless bodies.
Test the aperture ring for smooth, click-stop operation at each f-stop. Check focus ring for smooth travel from minimum focus to infinity. Inspect elements for haze, fungal spotting, or separation — common in lenses of this age. Verify the FD bayonet coupling engages and locks securely. Examine FD breech-lock ring for intact notches.