> > What they're really trying to say is that large studio flash units tend >to produce longer-duration pulses of light than small portable units. So >it may be necessary to limit your shutter speed to 1/125 to avoid flash >sync problems. >
No, that's not the real genesis of the problem. Studio flashes range from 1/10000 to 1/1000 of a second in flash duration. It's not how *long* the flash duration is, but *when* it is. The X sync standard is a bit loose in that regard. With the E-TTL protocol, the camera can tell the EX flash exactly when to flash, even when wireless (I imagine it sends out a notification to tell the unit to flash exactly 0.01 seconds from now). With the X-sync, it's a simple relay and the flash might take up to a couple of milliseconds to make up its mind. This is exacerbated when you have radio transmitters involved. The reaction time of the entire system has to be fast enough for the camera. That's why Canon has a rather conservative 1/125 X-sync for non-EX flashes. It's not that other flashes might not react fast enough, it's just they can't guarantee it. In any case, give it a try, you might find that your system is fast enough for 1/250 or even 1/500. Karen * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
