Canon's FD rectilinear ultra-wide — the 17mm f/4 S.S.C. with Super Spectra Coating.
The Canon FD 17mm f/4 S.S.C. was the Super Spectra Coated version of Canon's rectilinear ultra-wide, offered from 1973 within the first FD generation. The S.S.C. designation marked Canon's multi-coating applied to reduce flare and improve contrast over the earlier plain FD 17mm.
This is a manual-focus Canon FD lens with a fixed 17mm focal length and a maximum aperture of f/4. It is a rectilinear ultra-wide that keeps straight lines straight rather than curving them like a fisheye, covering a very wide field. Focus and aperture are set by hand on the FD barrel.
The lens gives a broad angle of view with well-controlled distortion, keeping verticals upright for architecture and interiors while opening up landscapes. Its short focal length delivers deep depth of field, and the multi-coating helps hold contrast when shooting toward bright sources, which is common with such a wide field.
On the used market this S.S.C. ultra-wide is valued for its coating and optical correction. Check the multi-element front group for haze, fungus and separation, verify the aperture blades are dry and the aperture ring clicks positively, and inspect the front element for scratches. It adapts cleanly to mirrorless bodies with an optics-free FD adapter.