Pentax A3000 - Page 42

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
t/1.4
in
combination
with
a
speed
of approx.
1,/3O
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
l/2.8lens
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
1OO. 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
1OO.
Metering
Range
and
Shutter
/ Aperture
Coupling
Range
The
metering
range
means
the range
of subject
luminance
within
which
the built-in
exDosure-
meter
works
to
control
exposure.
The
shutter/aperture
coupling
range
is that
part
of
the metering
range
within
which
shutter-speed
and
aperture value
can
be combined
for
proper
exposure
control.
When
you
use
a SOmm t/'1.4
normal
lens
and
an
ISO
1O0
film,
the metering
range
is
from EV
1
(t/1.4-1
sec.
or f
/2-2
sec.)to
EV 18
(f
/16-1/lOOO
sec. or t/22-1,/SO0
sec.).
The range
varies
according
to f ilm
speed
(lSO)
The variation
of the
metering
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 f ilm
speed
(lSO)
and the
brightness
of the
subject.
39o
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