Trigger External flash with GF1 - problem!

You can adjust the intensity of the flash on page 2 of the REC menu (in anything other than iA mode)

 

OK I'm confused. So you used the flash on the GF1 to trigger your WL optically? That won't work because of the TTl pre-flash.

Radio triggers will work nicely but you stuck at 1/180 shutter speed.

 

Do you mean you can't find the menu function, or when you dial in adjustment it doesn't make any difference?

 

This is an old thread, but I'm posting a reply based on my recent similar experience. I think minh0204 already pointed out the culprit. I suspect your off-camera external flashes synchronize with GF1's TTL pre-flash, effectively setting off the flashes before the shutter opens, thus resulting in underexposure. The fact that using a Canon flash in manual mode as the master (i.e., no pre-flash) does not result in underexposure is consistent with that suspicion.

I think the only solution is if your external flashes can synchronize with the pre-flash. My Nissin Di466, for example, has such function. It has two slave modes - so it can synchronize with either a pre-flash or the main flash. If your external flashes don't, you are out of luck.

 

I believe I know why

I'm 90% sure I know what's causing your problem. Most of Panasonic's cameras use a very "preflash" (short / low power) to calculate the exposure for flash photos. It's not perceivable to the eye. Your slave flashes are triggering to the "preflash", and consequently out of sync.

I had an older Panasonic flash that also had a slave mode where it would trigger from the camera flash. On my old "LC5" it worked great, but on later subsequent models it did the very same thing you describe. I'm told that B&H sells a slave trigger device that can trigger on the 2nd flash (the primary). I never purchased it or tried it, but I have seen it mentioned in a few discussions.