Nikon FA Instruction Manual page 21

-BASIC OPEAATION-contlnued------------------:
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 predeter-
mined exposure program. Thus, when actual exposure meas-
urement takes place at the time of shooting, the ideal combina-
tion 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 AI-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 progres-
sively chosen . With all other lenses, the normal program is in
operation . The high-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 AI-S, Nikon Series E, and AI -Nikkor
(including AI-modified) lenses ; with Nikon Teleconverters TC -200,
TC-300, orTC -14, the normal program is in operation .
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EVI
10 11 12 13 14 15
16
17
18
19
20
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The black line represents the normal program for an AI -S or AI-Nikkor
SOmm f/1.4lens with ASAIISO 100 film, whereas the green line represent s
the high-speed program for an AI -S Nikkor 135mm f/ 2 lens. For lenses
with different maximum apertures (e .g. an AI -S or AI-Nikkor 24mm f/2.8
which is indicated by a red line or an AI -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 conventional centerweighted metering.
Taking this into consideration, automat ic multi-pattern metering is pre-
programmed to automatica lly make exposure compensation by reducing
extreme brightness to EV
16-1/3.