earlier lenses occurs only when using a Canon New F-1 body with the AE Finder FN in aperture preferred AE mode. The New FD lenses' aperture rings were placed closer to the rear of the lens so that the aperture value is visible in the new F-1's viewfinder, via an optical prism. Earlier lenses' aperture scales do not align properly with the prism, and are therefore not visible. Aspherical, Fluorite or 'L' lenses An enhanced range of FD lenses was available to photographers who required the highest optical and mechanical performance. In addition to more robust mechanical construction, these lenses used a variety of special technologies, including ground aspherical surfaces, calcium fluorite optical elements, and ultra-low-dispersion glass. Canon used these means to achieve outstanding optical performance at the extremes of lens design: wide apertures and extreme focal lengths. Aspherical surfaces improved performance of wide-angle and standard lenses at very wide apertures. Ultra-low dispersion and fluorite elements virtually eliminated chromatic aberration at long focal lengths. The earlier versions of these lenses carried "AL", "Aspherical", or "Fluorite" indications on the front of the lens. The post-1979 'New FD' versions acknowledged all the exotic technologies under the single designation "L" (commonly believed to indicate 'luxury' or 'asphericaL'). Canon has continued the "L" designation, and the famous red ring around the lens front, in the current EF autofocus lenses for EOS cameras, where the symbol now officially stands for "Luxury." Macro lenses The FD series included a number of zoom lenses with close-focusing mechanisms, targeted at amateur photographers. The series also included three true macro lenses at 50mm, 100mm, and 200mm. These offered exceptionally close focusing and were corrected for flatness of field at close shooting distances. The 50mm and 100mm were marketed with extension tubes that allowed life-size reproduction. The 200mm can reach life size without additional extension. Special-purpose lenses Canon offered seven specialty lenses for the FD mount. The 35mm 2.8 Tilt-Shift lens is a perspective control lens. It may be tilted ±8 degrees for depth of field control, or shifted 11mm for perspective control. Though it uses the breech-lock mount, it is not literally an FD lens since its diaphragm is operated manually and it must be used with stop-down metering. The 85mm 2.8 Soft Focus lens is designed for portraiture. The photographer may introduce three levels of spherical aberration via a push-pull ring. Since aperture also affects the magnitude of