Canon FD

Functionality of the various Canon FD mount parts

The original FD mount provided for the installation of the lens with a rotary cap ring in the back of the lens (without turning the lens relative to the camera), but later this mount was replaced with an FDn mount (the so-called “New FD”, New FD, FDn ) allowing you to mount and remove the lens by simply turning the latter.

Unlike the previous FL system, the FD lens mount provided for the mechanical transfer of the lens aperture value and the set value of the jumping aperture to the camera’s exposure meter . This allowed the TTL exposure meter to be measured with the aperture fully open, previously unavailable in Canon cameras. In automatic exposure modes ( software , shutter priority ), automatic aperture setting was supported, for which it was necessary to rotate its control ring to special position “A”. The FD mount did not provide electrical communication between the camera and the lens, which excludes the transmission of information on the value of the focal length , and also does not provide the ability to perform autofocus . When used with modern digital cameras, which is possible through an adapter , data on such lenses are not displayed in the EXIF headers of the image, and exposure measurement is possible only with the working aperture value.

Similar technologies were used on all SLR cameras of that time, but later, most manufacturers adapted their standards to realize the possibility of interaction between the camera and the lens. Canon chose to develop a completely new standard ( Canon EF ).

Lens Coating

The first FD lenses had a polished metal frame in front for attaching a hood and other accessories, which is why such lenses are often called “chrome nose” (literally “lenses with a chrome front”). On the ring around the front lens were marked “SC” (Spectra Coating) and “SSC” (Super Spectra Coating). These designations indicated the presence of multilayer coatings on the lenses, while SSC implied a higher quality of this coating.

Lenses manufactured between 1973 and 1979 had the designation “SC” or “SSC” in red letters.

Since 1978 , after the appearance of the FDn mount, the designations on the lens body have disappeared. It was understood that most of the lenses at that time had SSC coating. However, the 50 / 1.8 lens continued to be produced with a SC coating.

L-series of lenses

Among the FD lenses, a line of lenses with the highest optical and mechanical quality stood out. They used a wide range of technologies, including aspherical and fluorite lenses.

After 1979, such lenses were marked with the letter “L” in the name and a red ring on the case. Prior to this, lenses in this series were labeled “Aspherical,” “Fluorite,” or “AL.”

Autofocus

All FD lenses provided for manual focus, but in the mid -1980s, Canon developed and released four autofocus FD lenses.

The following three lenses were manufactured under the AC brand (a variation of FD) in 1985 for the Canon T80 camera. These are AC 50mm f / 1.8, AC 35-70mm f / 3.5-4.5, and AC 75-200mm f / 4.5 lenses. The T80 was the first camera to interact with the lens through electronic contacts. However, the autofocus system in the framework of the FD mount was not developed. ^[one]

• Canon FL
• Canon ef
• Canon EF-S