High-Speed Sync - Canon SPEEDLITE 580EXII Mode D'emploi

c High-speed Sync
With high-speed sync (FP flash), the flash can synchronize with all
shutter speeds. This is convenient when you want to use aperture
priority for fill-flash portraits.
If you set a shutter speed that is the same or slower than the camera's
maximum flash sync speed, <F> will not be displayed in the viewfinder.
With high-speed sync, the faster the shutter speed, the shorter the
effective flash range will become. Check the LCD panel for the effective
flash range.
To return to normal flash, press the <E> button again. The <c>
icon will disappear.
Stroboscopic flash cannot be set.
Select <c>.
Press the <E> button so that
<c> is displayed.
In the viewfinder, check that the <F>
icon is displayed.
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