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01-30-2008, 10:29 PM   #1
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Is a Vivitar 225 Safe to try?

Hi everyone,

I picked up a Vivitar 225 for $10 at a pawn shop today and plan to use it for strobist type experiments later on with ebay triggers. I've heard the old Viv's had high trigger voltages and can hurt newer SLR's. Can anyone confirm that this is the case for this flash as well or was it just the 283/285's? I don't have a multimeter to try testing it unfortunately.

Anthropas

01-30-2008, 11:06 PM   #2
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Well, here's the standard link for checking appoximate trigger voltage values: Photo Strobe Trigger Voltages

Unfortunately, the Vivitar 225 isn't listed. If you can't get an answer here or borrow a multimeter from a friend, it might be worth spending $5-10 for a cheap multimeter to check the flash yourself.

The 225 is an old enough model that there is a good chance it has too high a trigger voltage to be used on your camera safely, though on a remote trigger I don't think it's as much of a problem.

I'm currently in the process of sourcing parts to build a circuit that will lower the sync voltage on my old Vivitar 3500, but haven't finished the design yet (buying a proper safe sync module would cost several times more than my flash is worth).
01-31-2008, 01:40 AM   #3
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Some same model flashes will have different voltages depending on where and when they were manufacturered so it is always best to check the voltage yourself. Your Vivitar 225 seems to have a trigger voltage over 150v, according to other users, after doing a google search. The rule of thumb max voltage for the Pentax DSLR's seems to be about 30Volts.

Anyway at $10 you still have a cheap off camera flash.

cheers
Keith
01-31-2008, 05:47 AM   #4
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QuoteOriginally posted by Steinback Quote
Well, here's the standard link for checking appoximate trigger voltage values: Photo Strobe Trigger Voltages

Unfortunately, the Vivitar 225 isn't listed. If you can't get an answer here or borrow a multimeter from a friend, it might be worth spending $5-10 for a cheap multimeter to check the flash yourself.
No it is the worst decision yoou can make, to spend 5-10 for a cheap multi meter. I did some comparisons a while back, link was called "flash trigger voltage" or something like that. depending on the meter, you can read as low as 10 volts on something that actually has a 200 V trigger voltage.
QuoteQuote:
The 225 is an old enough model that there is a good chance it has too high a trigger voltage to be used on your camera safely, though on a remote trigger I don't think it's as much of a problem.

I'm currently in the process of sourcing parts to build a circuit that will lower the sync voltage on my old Vivitar 3500, but haven't finished the design yet (buying a proper safe sync module would cost several times more than my flash is worth).
I would be very careful

see this link.

https://www.pentaxforums.com/forums/pentax-camera-accessories/18609-measuring...r-voltage.html

01-31-2008, 11:45 AM   #5
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Thanks for the responses guys, I think I'll resist the urge until I'm %100 positive it safe. I'll make sure to pick up a multimeter from a reputable brand; that's money well spent in my opinion.

Thanks again,

Anthropas
02-01-2008, 05:58 PM   #6
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QuoteOriginally posted by anthropas Quote
Hi everyone,

I picked up a Vivitar 225 for $10 at a pawn shop today and plan to use it for strobist type experiments later on with ebay triggers. I've heard the old Viv's had high trigger voltages and can hurt newer SLR's. Can anyone confirm that this is the case for this flash as well or was it just the 283/285's? I don't have a multimeter to try testing it unfortunately.

Anthropas
As long as the 225 is mounted on one of the wireless receivers (and therefore off-camera), it makes no difference anyway. I certainly wouldn't mount it on my camera, however.

CN
02-02-2008, 08:07 PM   #7
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Thanks for the correction Lowell, I've only ever dealt with digital meters and wasn't aware that analog meters had problems with certain circuit types.

If you meant to be careful about my sync circuit, I'm not too concerned about it. I'm looking to use an optorelay rated at 400 volts DC with a 2ms or better response time (1/180 of a second sync = approx 5.5ms). The relay is rated for significantly more abuse than I intend to submit it to, and I've got an electrical engineer around to double check my math plus a couple of scrap flashes around to test the circuit on before trying it out in the real world.
02-03-2008, 07:28 AM   #8
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QuoteOriginally posted by Steinback Quote
Thanks for the correction Lowell, I've only ever dealt with digital meters and wasn't aware that analog meters had problems with certain circuit types.

If you meant to be careful about my sync circuit, I'm not too concerned about it. I'm looking to use an optorelay rated at 400 volts DC with a 2ms or better response time (1/180 of a second sync = approx 5.5ms). The relay is rated for significantly more abuse than I intend to submit it to, and I've got an electrical engineer around to double check my math plus a couple of scrap flashes around to test the circuit on before trying it out in the real world.
Note regarding 1/180 of a second and sync timing.

what 1/180 of a second really means is that the sweep of the shutter blades could be up to that time, i.e. it takes 1/180 for the leading curtain to get to the top of the frame, and the trailing curtain begins to move at the instant the leading curtain gets there, with only a nano second of full frame open time.

In actuality, this is not the case, and the shutter probably opens much faster, but 2 mS is a considerable portion of th eremaining time that the shutter is fully open,

You will have problems, and I expect serious ones, with the 2 mS delay and flash powers above 1/4 power snce the trailing shutter curtain will be moving during the end of the flash, leaving part of the picture under exposed, especially if you shoot at maximum sync speed.

You may be better off with a High voltage transistor, perhaps a FET with suitable voltage rating and a small circuit to damp any transient overvoltages.

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