Vivitar 281 - trigger voltage

alanrockwood · Mar 4, 2019

Does anyone know what the trigger voltage is on the Vivitar 281 electronic flash?

I would like to use it on some canon EOS-type cameras, but I want to be sure the trigger voltage won't zap my camera.

Also, if anyone has a charger for that model I might be interested in it if it is not too expensive.

craigclu · Mar 4, 2019

I went through a lot of testing when someone was accumulating this data some years back. The generation of the 281 is likely to have a high trigger voltage and I would hesitate to trust it on electronic-relayed cameras until you measure or are assured of the voltage. Some innocent looking little flashes were measuring in the +300v ranges. I don't recall this flash and can only speculate to use some caution until tested.....

John Koehrer · Mar 4, 2019

I agree with craigclu and would also say that because when that flash was made there no component in the circuit to be affected by the higher voltage.

Chan Tran · Mar 4, 2019

I don't know about the 281. I do know about the 283. The newer version of the 283 has low sync voltage of about 6V or so. This version was made in China. The older versions made in Japan and Korea have high sync voltage. My 283 made in Japan has the sync voltage of 273V.

GRHazelton · Mar 5, 2019

Try this http://www.botzilla.com/photo/strobeVolts.html I haven't perused the site recently, but IIRC it includes, in addition to trigger voltages, voltage tolerances for a number of cameras. Some trigger voltages could give you a nasty shock

GRHazelton · Mar 5, 2019

Try this http://www.botzilla.com/photo/strobeVolts.html I haven't perused the site recently, but IIRC it includes, in addition to trigger voltages, voltage tolerances for a number of cameras. Some trigger voltages could give you a nasty shock

darkroommike · Mar 5, 2019

The 281 is ancient, not even a hot shoe, so old it didn't even make the botzilla list, so I am going to suggest
for an EOS camera, not just no but

HELL NO!!!
that said you could probably trigger it with an optical slave (not a new radio slave but an oldie like a peanut or a Vivitar SL1 or SL2.).

AgX · Mar 6, 2019

Flashes do not have shoes, hot or not... And this looks like a hot-foot to me:
https://www.vintagefindz.com/wp-content/uploads/images/products/p-7870-vivitarflash2.jpg

The hot-foot seemingly has a female PC connector to put the integrated PC-cable into:
https://encrypted-tbn0.gstatic.com/...AufOHCTT421ENYgivKptQyeU4iP25r5lQfCSELwIBUM5A

Was there ever an autoexposure flash that had no hot-foot?

miha · Mar 6, 2019

Looks like cold-shoe to me (Vivitar calls it shoe, mounting shoe to be precise, however foot makes more sense in my language as well).

jim10219 · Mar 6, 2019

The Phottix brand of wireless flash triggers can tolerate up to 300V of trigger voltage on the receiver. That's what I use because they work so well for questionable flashes (old Vivitars, Novatrons, etc.). You may have to get or make a sync cable though, as they don't have a PC outlet (on the receiver, they do on the transmitter). But they do have a headphone style jack and a normal hot shoe, and PC adapters for those are easy to come by. Some models pass TTL, others do not, so if that's an important feature for you, pay attention to that.

binglebugbob · Apr 18, 2019

I'd guess the odds of that flash frying your EOS are about 99%. As Chan Tran mentioned even in the later 283, the early ones had a high trigger voltage while the late ones had a safe trigger voltage. I still wouldn't put any older flash on my electronic camera without knowing the trigger voltage....

I don't know if the Wein Safe Sync is still available, but it was designed to go between a flash with high trigger voltage and the camera. It knocks the voltage down to a safe level. Research it for yourself, but that should be one way you could use your flash.

However, a later (used) flash with low trigger voltage would probably cost less than a Wein Safe Sync. https://www.bhphotovideo.com/c/product/245292-REG/Wein_W990560_Safe_Sync_Hot_Shoe_to.html

I don't see the point in destroying a $300 camera with a $10 flash.

alanrockwood · Apr 18, 2019

binglebugbob said:
I'd guess the odds of that flash frying your EOS are about 99%. As Chan Tran mentioned even in the later 283, the early ones had a high trigger voltage while the late ones had a safe trigger voltage. I still wouldn't put any older flash on my electronic camera without knowing the trigger voltage....

I don't know if the Wein Safe Sync is still available, but it was designed to go between a flash with high trigger voltage and the camera. It knocks the voltage down to a safe level. Research it for yourself, but that should be one way you could use your flash.

However, a later (used) flash with low trigger voltage would probably cost less than a Wein Safe Sync. https://www.bhphotovideo.com/c/product/245292-REG/Wein_W990560_Safe_Sync_Hot_Shoe_to.html

I don't see the point in destroying a $300 camera with a $10 flash.

I was able to buy a charger and measure the trigger voltage. It was about 45 volts. I agree it is a bad idea to think about using this flash on an EOS camera, and I can buy a cheap modern flash for a low enough price that it is probably not worth trying to use the Vivitar with a safe sync.

AgX · Apr 18, 2019

If you want to go for economics, there are still fllashes with low trigger voltages from the 80s, that likely can be got for a few dollars.
Have a look at the respective listings, but meter nonetheless, as even at one model there may have been changes and you do not want to use the older version.

kingbuzzie · Apr 19, 2019

To piggy back on this thread... will a flash hot shoe to PC sync cord adapter protect the electronics from a high trigger voltage?

MattKing · Apr 19, 2019

kingbuzzie said:
To piggy back on this thread... will a flash hot shoe to PC sync cord adapter protect the electronics from a high trigger voltage?

No.
They are simply a direct wired connection across the camera/trigger's synch circuit.

jim10219 · Apr 19, 2019

alanrockwood said:
I was able to buy a charger and measure the trigger voltage. It was about 45 volts. I agree it is a bad idea to think about using this flash on an EOS camera, and I can buy a cheap modern flash for a low enough price that it is probably not worth trying to use the Vivitar with a safe sync.

How'd you measure that trigger voltage? Because if you used a standard hand held DMM, it likely isn't able to react fast enough to the short impulse of a flash and give you an accurate reading. They'll usually show you a lower voltage than what it really outputs.

A good bench top or oscilloscope is the best way to do it. Another option is to look at the schematic and see how the trigger circuit was designed. If it's a direct feed off the tube, it's probably over 100 volts.

alanrockwood · Apr 19, 2019

jim10219 said:
How'd you measure that trigger voltage? Because if you used a standard hand held DMM, it likely isn't able to react fast enough to the short impulse of a flash and give you an accurate reading. They'll usually show you a lower voltage than what it really outputs.

A good bench top or oscilloscope is the best way to do it. Another option is to look at the schematic and see how the trigger circuit was designed. If it's a direct feed off the tube, it's probably over 100 volts.

Maybe I did it wrong, but here is what I did. I charged up the flash and then measured the voltage between the contacts on the hot shoe using a hand held dimital multi meter.

RalphLambrecht · Apr 20, 2019

alanrockwood said:
Does anyone know what the trigger voltage is on the Vivitar 281 electronic flash?

I would like to use it on some canon EOS-type cameras, but I want to be sure the trigger voltage won't zap my camera.

Also, if anyone has a charger for that model I might be interested in it if it is not too expensive.

the Vivitar series of electronic flashes are known for their high trigger voltages. I recommend to use them only in combination with a wireless radio trigger. Even inexpensive($20-30)models are ok!

AgX · Apr 20, 2019

jim10219 said:
How'd you measure that trigger voltage? Because if you used a standard hand held DMM, it likely isn't able to react fast enough to the short impulse of a flash and give you an accurate reading. They'll usually show you a lower voltage than what it really outputs.

A good bench top or oscilloscope is the best way to do it. Another option is to look at the schematic and see how the trigger circuit was designed. If it's a direct feed off the tube, it's probably over 100 volts.

Why should the meter show a lower voltage?

Well, the issue is its internal resistance.
If it is too low the resultant current is big enough to trickle the flash tube. Then no metering will be possible.

If it is high enough there is no short impuls as you wrote, but the static voltage of the trickle capacitator is measured.

I guess you refer to an intermediate resistance, too high to allow a sufficient trickle current, but still low enough to allow for a voltage drop.
This then would effect any voltage metering with this meter and not just that of the synch voltage.

Chan Tran · Apr 20, 2019

AgX said:
Why should the meter show a lower voltage?

Well, the issue is its internal resistance.
If it is too low the resultant current is big enough to trickle the flash tube. Then no metering will be possible.

If it is high enough there is no short impuls as you wrote, but the static voltage of the trickle capacitator is measured.

I guess you refer to an intermediate resistance, too high to allow a sufficient trickle current, but still low enough to allow for a voltage drop.
This then would effect any voltage metering with this meter and not just that of the synch voltage.

In this case an oscillocope is worse than a DMM as the scope generally only has an impedance of 1 megaohrms while a DMM would have 10 megaohms impedance.

Vivitar 281 - trigger voltage

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