GH2 How to make external flash trigger at the right time?

N

nickn

Member
Basically I'm trying to do what he's doing in this vid:


I have a gh2 and a ZE-FL70 flash which I've set in slave mode. I pop up the gh2's flash and take a picture. Both the gh2's flash and the ZE flash fire, but in the picture the external ZE flash's light does not appear. So I'm assuming it's firing too late.

However I've tried setting the gh2's shutter speed to a full second but the ZE's light still does not appear in the picture, so maybe it's somehow too soon.

What do I do to get this to work?
 
I tried turning the AF Assist Lamp off because maybe that was triggering the flash too soon. I also tried shooting with manual focus but neither worked.
 
stoneinapond said:
How are you connecting the external flash to the camera?
Click to expand...

He's got it in "slave" mode so it's not connected to the camera. With the original Canon digital Rebel, 300D which also had no external flash connection other than the hotshoe, the only way I could use external flash (AB800's) was to use a compatible "dedicated" (for Canon) small flash in the hotshoe with the flash itself set to Manual (no auto exposure). I set the manual output to the lowest level (1/32 power) and tilted it up or at a wall. The idea was to use a very weak flash to trigger the AB800 unit.

In manual mode the shoe mounted unit used no "preflash" to measure exposure and no "redeye" reduction. In that mode all it did was fire in synch with the shutter and then the "slaved" AB800 also fire in synch.

What is happening for the OP is that the flash in the shoe is still operating in an auto mode, and is using either a "preflash" to measure exposure or for redeye reduction, that preflash is tripping his external slave unit before the shutter opens. When the shutter opens the shoe mounted unit delivers the second and "real" flash it's going to but the slave has already fired and is starting to recharge.

Nick. If your shoe mount flash has a Manual mode with different output levels try setting it at the lowest and see if the external unit will fire in proper synch.

I've never tried this with my GH2 and I won't have to now since the GH3 has a standard PC flash socket and if I need to I can run a cord from one of my AB800's. The AB800 is an "Alien Bees" model 800 monolight, suitable for some studio use. It's from Paul C. Buff who also markets the "White Lightning" line of studio flash. The Alien Bees is an economy line.
 
Bruce Foreman said:
What is happening for the OP is that the flash in the shoe is still operating in an auto mode.
Click to expand...

If I open the built-in flash on the GH2, there is no way I could place an external flash into the hot shoe. There are several solutions (sort of) but I wanted to know how the OP had set up his external flash.
 
Bruce Foreman said:
He's got it in "slave" mode so it's not connected to the camera. With the original Canon digital Rebel, 300D which also had no external flash connection other than the hotshoe, the only way I could use external flash (AB800's) was to use a compatible "dedicated" (for Canon) small flash in the hotshoe with the flash itself set to Manual (no auto exposure). I set the manual output to the lowest level (1/32 power) and tilted it up or at a wall. The idea was to use a very weak flash to trigger the AB800 unit.

In manual mode the shoe mounted unit used no "preflash" to measure exposure and no "redeye" reduction. In that mode all it did was fire in synch with the shutter and then the "slaved" AB800 also fire in synch.

What is happening for the OP is that the flash in the shoe is still operating in an auto mode, and is using either a "preflash" to measure exposure or for redeye reduction, that preflash is tripping his external slave unit before the shutter opens. When the shutter opens the shoe mounted unit delivers the second and "real" flash it's going to but the slave has already fired and is starting to recharge.

Nick. If your shoe mount flash has a Manual mode with different output levels try setting it at the lowest and see if the external unit will fire in proper synch.

I've never tried this with my GH2 and I won't have to now since the GH3 has a standard PC flash socket and if I need to I can run a cord from one of my AB800's. The AB800 is an "Alien Bees" model 800 monolight, suitable for some studio use. It's from Paul C. Buff who also markets the "White Lightning" line of studio flash. The Alien Bees is an economy line.
Click to expand...

Thanks! By putting a 3rd flash in the camera shoe and not using the built in GH2 flash I can get the ZE to fire and appear in the scene. The ZE is advertised as being compatible with the GH2 but this appears to be an inaccurate claim to me.

Doing more research I find that the GH2 has a premetering flash plus the normal flash and there does not seem to be a way to disable the 1st. The manual simply states "The flash is activated twice. The interval between the first and second flash is longer when [ ], [ ] or [ ] is set."

I've tried disabling red eye compensation and setting flash syncro on 2nd. The only thing that actually works is using the 3rd flash. Thanks very much!!!
 
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Hi, Nick.

I finally watched the video and saw what he was doing. First off he used a Canon 60D and a 530EX III flash (also Canon, I suppose). The 60D controlling the popup flash probably works in concert with the Canon 530EX so both can fire in synch as the shutter opens.

Within the same brand it may work that way sometimes, but when you have a 3rd party flash like your Zeikos ZE FL70 that is "dedicated" to your GH2, it is dedicated and compatible as advertised but not to the extent you can trigger it in slave mode in synch with the popup flash.

I had a Canon 60D for awhile but can't remember if the "preflash" could be turned off all the way with the popup. But with what you have you are going to have to have a flash in the hotshoe serving the purpose of the popup plus the external ZE FL70.

This is a complex issue and most of the time we are not going to be able to use the popup to trigger an external in synch. But I'm glad you got something working.

One caution: Be very careful what you put in the hotshoe. Many older flash units had a very high trigger voltage and can "fry" some circuits in our cameras. Modern units made to work on recent cameras should be safe and if you ever get the "hankerin" to get into studio flash the Alien Bees units have a trigger voltage under 5v so they are safe to connect to a hotshoe adapter.

Hope I've been of some help.
 
Thanks, that's a great help.

Do you know if I get an actual Panasonic-brand flash that it will know how to correctly handle the double flash from the GH2?
 
I have no idea. That isn't something I would count on. Apparently Canon did it with the 60D but they didn't with the 300D I had for awhile. You'll have to ask that of Panasonic but the folks you talk to there may be "clueless".

Sorry I don't have a better idea.
 
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