High-speed sync guide number table – Canon 220 EX User Manual
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High-Speed Sync Guide Number Table
Shutter Speed
Guide Number (m/ft)
ISO 100
ISO 200
ISO 400
1/125
13.3/43.6
18.8/61.7
26.6/87.2
1/180
12/39.4
17/55.8
24/78.7
1/250
10.7/35.1
15.1/49.5
21.4/70.2
1/350
9.1/30
12.9/42.3
18.2/59.7
1/500
7.7/25.3
10.9/35.8
15.4/50.5
1/750
6.5/21.3
9.2/30.2
13/42.6
1/1000
5.4/17.7
7.6/24.9
10.8/35.4
1/1500
4.6/15.1
6.5/21.3
9.2/30.2
1/2000
3.8/12.5
5.4/17.7
7.6/24.9
1/3000
3.2/10.5
4.5/14.8
6.4/21
1/4000
2.7/8.9
4/13.1
5.4/17.7
FP Flash
• The Speedlite 220EX Guide Number changes
according to the high-speed sync operations. The
flash range decreases as the shutter speed
increases with FP flash.
• The limit of the flash range can be calculated with
the following formula: Guide Number
÷ the dis-
tance calculated from the aperture setting.
220EX(E) 15-10-2002 07:11 Pagina 22