Hey all On the weekend while shooting a wedding I had a problem where my flash stopped working on my camera. Other flashes would work, as would wireless triggers, so had to be the flash. I managed to survive the rest of the day using some donated wireless triggers (thanks Sean!) and it all turned out well. I did some looking around and found that the quick release mechanism and hot shoe on the 580EX II can become loose and connection can be flaky or just not there. Some instructions on fixing the issue can be found here: http://shimworld.wordpress.com/2008/02/28/speedlite-580ex-ii-hotshoe-fix/ I didn't need to remove the inner cover as my screwdrivers were thin enough to reach to the hot shoe mount shoes and I tightened them about a full turn. If anyone has this flash, it might be worth doing some preemptive maintenance so it doesn't fail at an important moment. If it is still under warranty send it in to Canon for a fix, otherwise do it yourself. Very simple. Over and out Craig -- Sent from my PC