BASIC OPERATION continued
Programmed Exposure Measurement Graph
In the programmed automatic exposure mode, the FA provides the optimum combination of aperture and shutter speed to match the film speed in use and the brightness of the scene. These combinations were arrived at through intensive research and then fed into the FA's microcomputer to provide a predetermined exposure program. Thus, when actual exposure measurement takes place at the time of shooting, the ideal combination on is selected, resulting in perfect exposures for every shot.
Moreover, the FA features two different exposure programs to match the lens focal length (applies only to Al-S Nikkor and Nikon Series E lenses) The normal program is for lenses less than 135mm; the high-speed program is for 135mm and longer (including zoom lenses whose longest focal length exceeds 135mm). To minimize camera shake with telephoto lenses, the high speed program does not go below 1/125 sec until the lens maximum aperture is reached: then slower speeds are progressively chosen. With all other lenses, the normal program is in operation The h gin-speed program is also automatically chosen by the FA when a Nikon Teleconverter TC-201, TC-301, TC-14A, or TC-14B is attached to Al S, Nikon Series E, and Al-Nikkor (including AI-modified) lenses; with Nikon Teleconverters TC-200, TC-300, or TC 14, the normal program is in operation.
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The black line represents the norma program for an Al-S or Al-Nikkor 50mm f/1.4 lens with ASA/ISO 100 film,whereas the green line represents the high-speed program for an Al-S Nikkor 135mm l/2 lens. For lenses with different maximum apertures (e.g. an Al-S or Al-Nikkor 24mm f/2 8 which is indicated by a red line or an Al-S Nikkor 200mm f/4 by a pink line), the graph is read from that particular aperture until intersection with the diagonal line and then downward along the same line. Solid program lines represent automatic multi-pattern metering, whereas solid and dotted lines centerweighted metering. In extremely bright lighting situations such as snow scenes, scenes at the beach etc exposure compensation of approx +2 EV is required with conventions centerweighted metering. Taking this into consideration, automatic multi pattern metering s pre programmed to automatically make exposure compensation by reducing extreme brightness to EV 16-1/3.
