Pentax PZ-70 PZ-70 Manual - Page 72

A33nvaciv

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SNOI1VII3d0 a33NVACIV Calculating the flash effective distance according to the camera-to-subject distance. Maximum flash distance aperture Minimum flash distance 5* Guide Number Selected Maximum flash distance When the distance to the subject is less than O.7m (2.3ft), flash cannot be used. If the flash is used within that distance, it causes vignetting in the picture corners, light is distributed unevenly and the picture may be overexposed. • The value 5 used in the formula above was obtained from the built-in flash. The guide numbers (GN) depend upon the film speed used as shown below. 15O25 • GN6.5 1SO2OO • GN18 15O5O • GN9.2 15O4OO - GN26 ISO1OO • GN13 If an ISO1OO film is in used at an aperture of f2.8, the flash effective distance is obtained as follows: Guide Number (13) f'2.8 4.6m 4.6 5 O.92m Thus, the flash effective distance is from approx. O.92m to 4.6m. Calculating the aperture according to the camera-tosubject distance Aperture = Guide Number tance Camera-to-subject dis- If the calculated aperture value is the one other than an f-stop on the aperture ring, for instance f /3, choose the next smallest aperture ring (f2.8 in this case). Built-in Flash effective range for Programmed TTL Auto Flash with ISO 400 film used Maximum Lens Aperture Effective Range f/1.4 approx. 0.9 - 6.5m (3.0 - 21.3ft) f/2 approx. 0.8 - 5.8m (2.6 - 19.0ft) f/2.8 f/3.5,f/4.7 f/5.6 approx. 0.7 - 4.6m (2.3 - 15.1ft) approx. 0.7 - 4.6m (2.3 - 15.1ft) approx. 0.7 - 4.6m (2.3 - 15.1ft)

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SNOI1VII3d0
a33NVACIV
Calculating
the
flash
effective
distance
according
to
the
camera
-to
-subject
distance.
Maximum
flash
distance
Guide
Number
Selected
aperture
Minimum
flash
distance
Maximum
flash
distance
5*
When
the
distance
to
the
subject
is
less
than
O.7m
(2.3ft),
flash
cannot
be
used.
If
the
flash
is
used
within
that
distance,
it
causes
vignetting
in
the
picture
cor-
ners,
light
is
distributed
unevenly
and
the
picture
may
be
overexposed.
•
The
value
5
used
in
the
formula
above
was
obtained
from
the
built-in
flash.
The
guide
numbers
(GN)
depend
upon
the
film
speed
used
as
shown
below.
15O25
•
GN6.5
1SO2OO
•
GN18
15O5O
•
GN9.2
15O4OO
-
GN26
ISO1OO
•
GN13
If
an
ISO1OO
film
is
in
used
at
an
aperture
of
f2.8,
the
flash
effective
distance
is
obtained
as
follows:
Guide
Number
(13)
f'2.8
4.6m
4.6
5
O.92m
Thus,
the
flash
effective
distance
is
from
approx.
O.92m
to
4.6m.
Calculating
the
aperture
according
to
the
camera
-to
-
subject
distance
Aperture
=
Guide
Number
Camera
-to
-subject
dis-
tance
If
the
calculated
aperture
value
is
the
one
other
than
an
f-stop
on
the
aperture
ring,
for
instance
f
/3,
choose
the
next
smallest
aperture
ring
(f2.8
in
this
case).
Built-in
Flash
effective
range
for
Programmed
TTL
Auto
Flash
with
ISO
400
film
used
Maximum
Lens
Aperture
Effective
Range
f/1.4
approx.
0.9
-
6.5m
(3.0
-
21.3ft)
f/2
approx.
0.8
-
5.8m
(2.6
-
19.0ft)
f/2.8
approx.
0.7
-
4.6m
(2.3
-
15.1ft)
f/3.5,f/4.7
approx.
0.7
-
4.6m
(2.3
-
15.1ft)
f/5.6
approx.
0.7
-
4.6m
(2.3
-
15.1ft)