Nguide number (gn) – Pentax AF-360FGZ User Manual
Page 81
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n
Guide Number (GN)
Guide numbers indicate flash light intensity. The larger
the number, the farther you can reach with your flash.
From the guide number, you can easily obtain the
proper aperture setting required for an optimum
exposure.
l
Depending on the camera and lens you are using,
the effective flash range may be displayed. (Refer to
page 78.)
Guide Number Table
*With the wide-angle panel attached
Aperture (f/stop) =
GN/flash-to-subject distance (m)
ISO
Flash
light
intensity
Camera format
Zoom position
35mm
85mm
70mm
50mm
35mm
28mm
24mm
*20mm
645
150mm 135mm 100mm
70mm
55mm
45mm
*35mm
67
190mm 180mm 120mm
90mm
70mm
60mm
*55mm
DIGITAL
58mm
48mm
34mm
24mm
19mm
16mm
*13mm
ISO100
1/1
36
33
30
25
22
21
14
1/2
25
23
21
18
16
15
10
1/4
18
16.5
15
12.5
11
10.5
7
1/8
12.5
11.5
10.5
9
8
7.5
5
1/16
9
8
7.5
6
5.5
5
3.5
1/32
6
5.5
5.4
4.3
4
3.6
2.5
00_AF360FGZ.book Page 79 Tuesday, June 13, 2006 12:09 PM