[rpvincent]

I have a Rebel XS w/ a hotshoe to PC cord adapter and sync cord to a AlienBees 160ws flash. It consistantly fires the flash when not in full screen photo booth mode by either pressing the shutter button on the camera or clicking the button on screen.

However, when the program is put into full screen mode and a photo booth session is started, there are times where the picture takes but the flash doesn't.

I've tried various restart, power cycle, unplug routines with the cam and pc that has provided temporary correction but the problem comes back after a while. The physical connection from the cam to the flash is not the issue.

Any ideas?

[rpvincent]

I did more testing and it turns out that the external flash won't fire when the live view mode is active. Turning off live view completely solves this problem.

Is this a new bug or is that how it was in older versions?

[jdshepard]

I'm having the same issue as well using the latest version of the software.

[Chris Breeze]

It's a limitation of the camera not the controlling software. If you operate the camera standalone (i.e. not connected to the PC) non-Canon flashes may not fire when live view is active. I don't know whether this is a problem with the way Canon have implemented live view or whether it is because some non-Canon flashes aren't 100% compatible.