Paul C. Buff, Inc. Technical Forum

I used two Einsteins today, both of them brand-new. Although I had tested them a few times before, this was the first commercial shoot I used them on. They worked normally for the first few minutes, then suddenly started flashing uncontrollably. I tried turning them off and on, but every time I turned them on they continued to flash rapidly. The CST is perfectly fine, no battery problems.

The only thing I can imagine is that there was some kind of interference. Obviously, professional flashes should be designed in such a way that interference is rarely a problem, but perhaps this isn't the case with the Einsteins. Has anyone had this problem?

The lights would not be susceptible to radio interference, that would be a function of the remotes. And honestly, I have never heard of an instance where the a CyberSync was triggered from interference.

Were your slave eyes on? What type of environment were you shooting in? Was there anything sharing the circuit that may have introduced noise to the AC line? Were you using a (properly) grounded AC outlet? Were you using anything that may have introduced a bad ground (extension cord, power strip, etc)? Were there fluorescent lights turned on?

Some answers to your questions:

Were your slave eyes on?
Yes, the slave eyes were on.

What type of environment were you shooting in?
It was a small laboratory, with a number of electrical things around.

Was there anything sharing the circuit that may have introduced noise to the AC line?
There was nothing in the same outlet, but there were many outlets in the room, with machines plugged into them.

Were you using a (properly) grounded AC outlet?
The outlet was grounded, I imagine.

Were you using anything that may have introduced a bad ground (extension cord, power strip, etc)?
I was just using an electrical cord - the same ones that I've used on many shoots.

Were there fluorescent lights turned on?[/quote]
Yes, there were some overhead fluorescent lights, but not particularly strong.

Another thing to note is that BOTH flashes had the same problem, though not using the same electrical cords, nor the same outlet.

Ben

The problem is both flashes firing, and the slave eyes are on. If there was a problem with just one light firing on its own, the other light would still fire due to the slave eye. This would not indicate a fault in the second light, as it is doing what it is designed to do (fire when it sees a flash).

Flourescent lights flicker, and some flicker more noticably than normal. This can trigger the optical slave eye. If you are using remotes turn the slave eye off.

If an outlet is a two prong outlet, then it is not grounded. An ungrounded outlet can cause the lights to fire on their own, though not always.

An extension cord can wear over time, and the grounding can fail. However, this is not an issue if the outlet is not grounded anyway.

If machinery is sharing a circuit with your flash, there is the potential for electrical noise. This could account for the rapid firing. Also, some industrial locations will have warning or caution strobes which could set of the slave eye.

Thanks for the suggestions, those sound like possible causes.

I don't imagine the outlet would be a problem, I've been shooting with Alien Bees for nine years, using two-pronged outlets, and never had a problem.

Electrical noise could be a problem I suppose, but again, I've never had such a problem before.

It sounds like the slave eyes could have caused the problem - perhaps the fluorescent lights affected them somehow...although there weren't many fluorescent lights, so that would also be a little strange.

Anyway, I guess my only option at this point is to return to the location where I shot, and try testing the flashes there. It's deeply frustrating that I must do this, partly because of the time involved, but also the embarrassment of returning to my client's location. Before buying these lights, I was also considering Profoto. Now I'm wondering if I shouldn't have chosen Profoto instead for their 'superior reliability'...

Hi Shashinka

I experienced the same flashing, but in a controlled environment. The lights were fine and then one started to misbehave. Not a fun experience when they turn the place into a disco!

If you try all of the other advice and it still happens, try pulling the battery from the CST. You mentioned that you have AB's so possibly the CST is not new like the Einsteins... and has an older battery?

I attributed my problem to having a battery that had enough juice to trigger the lights but possibly low enough to also misbehave too. I replaced the CST battery and haven't seen the problem since. It could have been a coincidence, but it's an easy test to rule it out.


j

Thanks for sharing your experience, J!

Yes, it seems that usually this rapid flashing is caused by a low battery in the CST. In my case, however, the CST, as well as the two flashes, were all brand-new. I even checked the battery by pressing the little button, and it flashed one time, a sign that the battery is OK.

What's really strange is that BOTH flashes had this problem during the same shoot, which suggests that they were 'reacting' to something in the room. The only explanation I can think of is that the slave eyes on both flashes were on, so possibly they picked up some signal which caused the flashes to fire. I'm returning to the location tomorrow to try to replicate the problem, and hopefully find a solution. Will post the results after that.

2 Einsteins on the shoot, both w/ optical slaves, was there a 3rd light that was triggered by the CST?

If only 2 strobes were in use, the optical slave should be turned off on 1 unit. Or, turn off the optical slaves entirely if you are using the CST with receivers on each unit.

I've discovered the cause of the problem! I went back to the location today, and tried using the flashes, first with the slave eye turned off, then turned on. When I turned the slave eye on, the overhead fluorescent lights would immediately make the flash start popping, but when I turned the slave eye off, the flashes worked normally.

So, the solution from now on is very simple: turn off the slave eye, unless absolutely necessary.

Although I'm happy that this problem has been resolved, I'm still surprised that PCB doesn't warn people more strongly about the slave eye. It's pretty alarming when your flash goes crazy in the middle of a shoot.

glad it's all sorted out. A funny Greg Heisler story:



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