Pentax PZ-20 PZ-20 Manual - Page 79

Snoilvemo, 133nvain

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When in Aperture-Priority AE or Metered Manual Expo- sure Mode This mode is useful to take a flash photograph with a selected in-focus range (depth of field) by setting a desired aperture. In the Aperture-Priority AE Mode, the shutter speed changes according to the ambient brightness, making flash photography easy. • The shutter speed changes in the range from 1/100 to 1/30 sec., and the slowest shutter speed depends on the focal length of the lens mounted on the camera. When a lens made before the Pentax A-series is used, the camera uses the shutter speed of 1/100 sec. Calculating Flash Effective Distance According to the Selected Aperture Maximum flash distance = GN*-- Selected aperture Minimum flash distance = Maximum flash distance - 5 When the distance to the subject is less than 0.7m, flash cannot be used. *GN: Guide Number Calculating the aperture according to the camera-to subject distance Aperture = GN ÷ Camera-to-subject distance If the calculated aperture value is the one other than an fstop on the aperture ring, for example f/3, choose the next smallest aperture that is an f-stop on the aperture ring (f/2.8 in this case). The guide numbers depend upon the film speed used as shown below. ISO25 - GN6.5 ISO200 -- GN18 ISO50 - GN9.2 ISO400 - GN26 ISO100 -- GN13 f an ISO100 film is used at an aperture of f/4.7, the flash effective distance is obtained as follows: GN13 f/4.7 = 2.8m 2.8 ± 5 = Approx. 0.56 Thus, flash effective distance ranges from approx. 0.7m to 2.8m. 75 SNOILVEMO 1:133NVAIN III

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When
in
Aperture
-Priority
AE
or
Metered
Manual
Expo-
sure
Mode
This
mode
is
useful
to
take
a
flash
photograph
with
a
selected
in
-focus
range
(depth
of
field)
by
setting
a
desired
aperture.
In
the
Aperture
-Priority
AE
Mode,
the
shutter
speed
changes
according
to
the
ambient
brightness,
making
flash
photography
easy.
•
The
shutter
speed
changes
in
the
range
from
1/100
to
1/30
sec.,
and
the
slowest
shutter
speed
depends
on
the
focal
length
of
the
lens
mounted
on
the
camera.
When
a
lens
made
before
the
Pentax
A
-series
is
used,
the
camera
uses
the
shutter
speed
of
1/100
sec.
Calculating
Flash
Effective
Distance
According
to
the
Selected
Aperture
Maximum
flash
distance
=
GN*--
Selected
aperture
Minimum
flash
distance
=
Maximum
flash
distance
-
5
When
the
distance
to
the
subject
is
less
than
0.7m,
fl
ash
cannot
be
used.
*GN:
Guide
Number
Calculating
the
aperture
according
to
the
camera
-to
subject
distance
Aperture
=
GN
÷
Camera
-to
-subject
distance
If
the
calculated
aperture
value
is
the
one
other
than
an
f-
stop
on
the
aperture
ring,
for
example
f/3,
choose
the
next
smallest
aperture
that
is
an
f-stop
on
the
aperture
ring
(f/2.8
in
this
case).
The
guide
numbers
depend
upon
the
film
speed
used
as
shown
below.
ISO25
-
GN6.5
ISO200
--
GN18
ISO50
-
GN9.2
ISO400
-
GN26
ISO100
--
GN13
f
an
ISO100
film
is
used
at
an
aperture
of
f/4.7,
the
flash
effective
distance
is
obtained
as
follows:
GN13
f/4.7
=
2.8m
2.8
±
5
=
Approx.
0.56
Thus,
flash
effective
distance
ranges
from
approx.
0.7m
to
2.8m.
75
SNOILVEMO
1:133NVAIN
III