creepy 580ex/430ex question

[shutterfiend]

Last night, I had my 430 (slave) on a stand with an umbrella and the 580 (master) on camera. I had just finished taking a few pictures of my daughter and was reviewing them on camera when... both flashes lit up real brightly for about a second or two!!!

I took some test shots after, they were fine. I checked the history of the house and it doesn't seem likely that it was built on a graveyard. What could possibly have caused the flashes to go off like that? Any help would be appreciated.

[cosworth]

You pressed the DOF preview button.

[shutterfiend]

Thanks. I'll have to try it out tonight. I'll call the witch doctor off right now !!!

[Titus213]

It's actually a useful function - for finding coins in dark corners.

[Nightscape]

what is that function for anyways?

[cosworth]

Dpepth of field preview and modelling flash.

See your bokeh/focus range and see your flash shadows.

[Curtis N]

They call it a modeling light. Lets you see the light from the flash. Pretty worthless actually, but I have used it to get the attention of uncooperative subjects.

[Cadwell]

Handy if you drop a CF card in the dark... that's about it.

[Nightscape]

How many times do you need to do that before the batteries are dead? Not many.