Speedlite firing for no reason

[dont]

I have a strange problem that's occurred ever since I bought my first 580EX and

used it with my 20D. After about 15 or 30 minutes the flash would emit this 1

second flickering light with a slight buzzy sound. Then I would hear it recycle.

This would happen perhaps 2 times within minutes, then stop for a while.

 

Any clues as to what's wrong? I have 2 580EX's and switching between them

doesn't stop the problem, so I'm thinking it's the 20D camera body that's the

culprit. Other people I know who have the same flash/body combo's said its never

happened to them.

[peter_keightley]

Mine does this if I press the depth of field preview button on my 350d with the 580 mounted.

[steve_dunn2]

<p>What the first response describes is the only situation in which I've seen and heard what you're describing, and the only time I've seen or heard it is when I've triggered modelling flash, again as described by the first response.</p>

[alec_myers]

Are you inadvertantly hitting the depth-of-field preview button? That's what triggers the modeling flash.

[mike_broderick]

There must be an echo in here....Sounds to me as well as if the DOF preview button is being pressed. I suppose some sort of weird electrical fault could trigger that, but it's more likely (IMO) you're triggering it by accident.

[dont]

Thanks for all the quick replies -- and making me blush from embarrassment! I was totally pressing the DoF button inadvertently!

 

So I guess I should take some preventive steps to avoid blinding further victims of my dumbass... how about a bottle cap and duct tape?