What are your camera settings (in external flash control menu) for Av mode?
Are you shooting in Av?
"DAZNOTE: It’s important that when shooting in Auto mode your camera, at least Canon cameras, be set to Aperture Priority. This is the only Auto mode that works for High Speed Flash Sync"
source:
http://digitalprotalk.blogspot.ca …echniques-to-improve.html![]()
















