Nikon SB-28 Instruction Manual page 53

NOTE
—In the example, at 1/8 flash output level, the flash will fire three times per
frame at a frequency of 4 flashes per second.
Maximum number of repeating flashes per frame
Frequency*
1-2 Hz
3 Hz
4 Hz
5 Hz
6 Hz
7 Hz
8 Hz
9 Hz
10 Hz
20-50 Hz
*Frequency (Hz) represents the number of flashes per second. The higher the number, the
shorter the flash firing interval.
Flash output level
M1/8 M1/16
14 30
12 30
10 20
8 20
6 20
6 20
5 10
5 10
4 8
4 8
Frequency (Hz)
Flash output level
Number of repeating flashes
per frame
M1/32
60
60
50
40
32
28
24
22
20
12
M1/64
90
90
80
70
56
44
36
32
28
24
53