Nikon SB-28 User Manual
Page 51
% guide numbers vary with the ISO film speed, shutter speed, and zoom-
head position.
• For film speeds other than ISO 100, multiply the guide numbers by the
factors shown in the above chart.
For example, for a film speed of ISO 400, with the zoom-head adjusted to 35mm,
and a shutter speed of 1/500 sec., the
% guide number is 12 x 2 = 24 (m), or
39 x 2 = 78 (ft).
Notes on flash photography in FP High-Speed Flash sync
%
• Do not use the built-in wide flash adapter.
When used, M20 or M18,
ƒ and % blink on the LCD panel as a
warning.
• Detaching the SB-28
When you remove the SB-28 from the F5, F100, F90X/N90s or F90-
Series/N90, be sure to cancel FP flash operation. If the flash is removed
with the FP setting,
% blinks as a warning.
51
Shutter speed
1/250 sec.
1/500 sec.
1/1000 sec.
1/2000 sec.
1/4000 sec.
Zoom-head position
24mm
28mm
35mm
50mm
70mm
85mm
14/46
15/50
17/56
20/65
23/74
24/77
10/33
11/36
12/39
14/46
16/52
17/56
7/23
7.5/25
8.5/28
10/33
11/36
12/39
5/16
5.3/17
6/20
7/23
8/26
8.5/28
3.5/11
3.7/12
4.2/14
5/16
5.7/18
6/20
% guide numbers (at ISO 100; for meters/feet)
Factor
ISO film speed
x 0.5
x 0.71
x 1.4
x 2
x 2.8
25
50
200
400
800
Adjustment factors for other ISO film speeds