ok : for the 300D, it appears you shoot in M mode and the flash will adjust accordingly.
you must however shoot with High Speed Sync flash
*ie: on 420EX, switch to that symbol*
*on 550, press the +- button together..*
otherwise your max shutter speed is limited to 1/200
in anycase, that's what went wrong the whole day at SBG last sat. forgot how to turn on high speed sync flash on the 550EX..
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