A generic Canon 100mm f/2.8 listing — likely the FD, EF, or EF Macro depending on specific item.
This Canon 100mm f/2.8 with unspecified mount represents one of several Canon 100mm f/2.8 designs produced across different Canon lens mount generations. Without confirmed mount identification, it may be an FD, FL, or other Canon film-era 100mm prime. Canon produced 100mm f/2.8 designs across multiple mount eras.
Canon's 100mm f/2.8 designs across different mount generations share the same focal length and maximum aperture, with optical formulas varying by generation. All film-era Canon 100mm lenses (FD, FL) use manual focus and manual aperture. Specific multi-coating level depends on which Canon era this example represents.
Canon film-era 100mm primes are popular for adaptation to modern mirrorless systems given their optical quality and the 100mm portrait/moderate telephoto perspective. The absence of confirmed mount information means buyers should inspect the bayonet carefully before purchasing. FD and FL mounts are visually similar but mechanically different.
Determine the specific mount type by examining the bayonet geometry — Canon FD uses a chrome breech-lock ring, Canon FL uses a different ring configuration. Check aperture ring for smooth operation. Inspect element condition. Verify focus ring operation. Confirm the specific mount before ordering an adapter for mirrorless use.