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The shutter-speed and aperture combination In
the Programmed AE mode is shown in the chart.
The red line represents the variation of shutter-
speed and aperture combination with an f/1.4 lens.
Note that only the shutter-speed slows down after
the lens aperture reaches Its limit of f/1.4 in
combination with a speed of approx. 1/30 sec.
When you use a lens with a different maximum
aperture, the exposure program varies the
aperture and the shutter-speed in combination
until reaching the maximum aperture of your
lens. For example, with an f/2.8 lens the program
varies the combination as shown by the red
dotted line. Note that only the shutter-speed
changes after the maximum aperture is reached.
The fine red line in the Programmed AE diagram
indicates the Automatic Exposure control range
for a lens with minimum aperture smaller than
f/22, or for a film with ISO speed other than 100.
The fine red-dotted line indicates the range for
a lens with maximum aperture smaller than f/1.4,
or for a film with ISO speed other than 100.
Meter coupling range and Shutter/Aperture
coupling range
The meter coupling range means the range of
subject luminance within which the built-in
exposure-meter works to control exposure. The
shutter/aperture coupling range is that part of the
meter coupling range within which shutter-speed
and aperture value can be combined for proper
exposure control. When you use a 50mm f/1.4
normal lens and an ISO 100 film, the meter
coupling range is from EV 1 (f/1.4-1 sec. or f/2-2
sec.) to EV 18 (f/16-1/1000 sec. or f/22-1/500
sec.). The range varies according to film speed
(ISO), The variation of the meter coupling range is
shown by slanting lines which shift with ISO
ratings. The frame in the center shows the meter
and shutter/aperture control coupling range.
EV (Exposure Value)
EV represents a combination of the shutter-speed
and the lens aperture which Is determined by
the film speed (ISO) and the brightness of
the subject.
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