SD550 often refuses to fire

[thecovetrix]

I have an SD550 in the Canon housing (internal strobe). The photos are great - but the camera refuses to fire about a quarter of the time when it's underwater. The flash lightning bolt flashes on the display. After a few tries it fires - usually.

Is this a function of the camera not being able to focus? It only happens underwater. But I've had it happen snorkeling in 80-degree water and 120 feet deep 45-degree water, so I'm guessing it's not a temperature or pressure thing.

Is this a common problem?

 

[mazeingerz]

My canon s230 has the same problem. I usually just turn off and on after every shot and now the flash always triggers.