EOS 3 sync speed question

<p>I've borrowed an EOS 3 for a shoot tomorrow morning, haven't had a chance to test the max sync speed result but I'm puzzled about what the manual says: " The EOS 3 can synchronize with compact, non-Canon flash units at 1/200 sec or slower shutter speeds. With larger studio flash, the sync speed is 1/125 sec. or slower. "<br>

This is the only time 1/125 sec is mentioned in the manual, other times they always say 1/200 sec.<br /> I don't quite understand why a larger unit will have a different max sync speed and that's why I've posted this. I'm shooting with an Elinchrom RX 600, what is my max sync speed with this unit?</p>

<p>The sync speed depends on how fast the flash delivers the light. Canon flashes at max power will generate a a light pulse that is a little shorter than 1/200 of a second. A larger studio flash may be able to generate a light pulse that is much longer. You will have to look at your manual for your flash or do some tests with your equipment to determine which setting s work best for your particular flash.. </p>

<p>Usually I need to sync with most studio flash at 1/60 or slower. 1/125 isn't always reliable. Doesn't matter if it's the main light as the strobe duration is so short it freezes any human movement.</p>

<p>i don't know about the technical aspects of how and why is it that way, i can only tell you that i used to do quite a lot of studio work with the eos3 (what a camera!)and never went past 1/125. i did some tests with faster speeds when i picked up my first strobes and the results were- 1/125- OK 1/160- too fast.</p>

<p>Assumption is that large studio strobes may take longer to reach max power, so 1/125" is safe bet. If you wan to to be sure, just test with different shutter speed - appropriate shutter speed will result in fully-lit frame, if you see part frame lit and the other isn't (depening on ambient lighting difference may be big or small), then shutter speed was too short.</p>