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10-04-2009, 04:54 PM   #1
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voltage question

I use an istD.

Can anyone tell me how much voltage it can endure from a flash unit?

I was using an old Vivitar 2800 (4 AA batteries) with a Wein Safe Sync. Suddenly the safe sync is not working. Pressing the button on the side fires the flash, but it must not be making a good connection with the hot shoe.

If anyone has a suggestion to remedy this, I'd love to hear it.

Also, I have a very old small Pentax flash. It came as part of a set with a P3N years ago. It only uses two AA's. Would the voltage be low enough to use with the istD?

I think I remember reading that each AA battery produces 1.5 volts. If that is correct, this little flash produces only 3 volts.

The easy answer is to buy a new Pentax digital flash. The trouble with that plan is financial. At the moment photo equipment is not at the top of my must buy list.

Any information will be appreciated. Thanks.

10-04-2009, 06:12 PM   #2
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remember, that flash doesn't just use the instantaneous power from the batteries, it charges with a capacitor. I have heard the 2800 can hit 300v which isn't safe for the hotshoe. Pentax should be okay up to around 30v. I have a 2800-d which hits around 10v or so and is safe. Make sure to measure the voltage of the flash prior to using it on the camera.
10-05-2009, 05:29 AM   #3
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QuoteOriginally posted by ibdull Quote
Can anyone tell me how much voltage it can endure from a flash unit?
30V seems to be the correct answer but note that all Pentax flashes stay below 5V.

If you cannot measure the voltage on your flash yourself (make sure to use a digital voltmeter and fresh batteries), check out the recorded strobe trigger voltages.

You may consider some radio triggers, like the Cactus V4. They also guarantee a safe operation and get the flash away from the camera.

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