Canon 220 EX - Manual (Page 22)

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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