Canon 220EX - Manual (Page 23)

FP Flash
High-Speed Sync Guide Number Tabie
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
1^ • The Speedlite 220EX Guide Number changes
i-ii according to the high-speed sync operations. The
flash range decreases as the shutter speed
increases with FP fiash.
• The limit of the flash range can be calculated with
the foiiowing formula: Guide Number the dis­
tance caicuiated from the aperture setting
22