Accidental Flash

First I use a 580EX on a XTi with a battery grip attached.

I have been noticing that often my flash fires at seemingly random times (often when I am carrying it at my side). One pro told me it was my FEL being fired accidently by the way I held the camera and grip (he thought my thumb was triggering the "*" button on the grip accidently). Since he mentioned this, I try to make sure I touch neither of the "*" buttons (on the grip or the camera itself), but I still seem to get accidental flashes going off.

Is there some other way this could be happening I have missed? Is there some change in settings I could make to futher isolate the cause, and then eliminate it?

Thanks in advance to anyone who can figure this one out or has had it happen to them also (I used the same flash, battery grip setup with my 300D and never ran into this ...).

Maxdave

Change custom function 4 on the XTi to 1 and see if the problem persists.
Note - This makes the * button your autofocus button. It takes some acclimation but gives you greater control over the autofocus process.

Also make sure you aren't hitting the DOF preview button (which activates the modeling light), or disable the modeling light via custom function on the 580EX.

Maxdave - I am seeing the same behavior with a 430EX on my XTi (w/o battery grip). In my case, the "random' flashes seem to come in groups of 3, but otherwise do indeed seem random, with perhaps some correlation to jiggling or shaking the camera (!) You still seeing the behavior?

Maybe static electricity.

Heh - after watching my hands a little more closely, I think i am hitting the "*" key after all, and that's causing the FEL flash to fire. Oops. Good call!

I agree with you ... I have since got a 40D with the battery grip, and it never happens with it.