Canon Speedlite 580EX II Manual page 25

To avoid overheating and deteriorating the flash head, do not use stroboscopic
flash more than 10 times in succession. After 10 times, allow the Speedlite to
rest for at least 15 min. If you try to use the stroboscopic flash more than 10
times in succession, the firing might stop automatically to protect the flash
head. If this happens, allow the Speedlite to rest for at least 15 min.
Stroboscopic flash is most effective with a highly reflective subject
against a dark background.
Using a tripod, a remote switch, and external power source is recommended.
A flash output of 1/1 or 1/2 cannot be set for stroboscopic flash.
Stroboscopic flash can be used with "buLb."
If the number of flashes is displayed as - -, the firing will continue until the shutter closes or
the battery is exhausted. The number of flashes will be limited as shown by the table below.
Maximum Stroboscopic Flashes
Hz
Flash Output
1/4
1/8
1/16
1/32
1/64
1/128
Hz
Flash Output
1/4
1/8
1/16
1/32
1/64
1/128
If the number of flashes is displayed as - -, the maximum number of flashes will
be as shown by the table below regardless of the firing frequency.
Flash Output
Flash Count
1 2
7 6
14 14 12
30 30 30
60 60 60
90 90 90
100 100 100
10 11 12 - 14 15 - 19 20 - 50 60 - 199
2 2
4 4
8 8
20 20 20
50 40 40
70 70 60
1/4 1/8 1/16
2 4
3 4 5
5 4 4
10 8
20 20
50 50
80 80
100 100
2 2 2
4 4 4
8 8 8
18 16
35 30
50 40
1/32 1/64
8 12 20
6 - 7 8 - 9
3 3
6 5
20 10
40 30
70 60
90 80
2
4
8
12
20
40
1/128
40
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