flash voltages

Thank you, nobbylon.
[edit] Would someone reading this please say how trigger voltage is measured?
 
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payasam said:
Thank you, nobbylon.
[edit] Would someone reading this please say how trigger voltage is measured?
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It is measured with a volt-meter, across the primary terminals. For example with a simple flash with hot-shoe terminals, there will be a main terminal in the centre of the base of the hot-shoe, and another terminal on the side of the bracket that slides into the hot-shoe. Make sure the flash is fitted with fresh batteries and switched on and charged. Set your volt-meter to measure DC Voltage, starting at the 1000v range just in case it is a high-voltage flash. Use the probes to make contact with the terminals on the flash foot described above. You should get some reading - on the 1000v range it might show 002 if the actual voltage is 2 volts. Gradually select lower a voltage scale until you get an accurate reading. My modern Pentax flash shows 2.92 volts across the terminals. I have one old flash, a small one that takes two AA batteries, that has a trigger voltage of 177v!

Most modern "dedicated" flashes will also have extra pins on the base (surrounding the centre contact) which carry information for the circuitry that controls the TTL (Through-the-lens) or P-TTL (TTL with Pre-flash).
You need to avoid these when making this test.
 
As a supplementary note - in order to get an accurate reading the meter needs to have a high input impedance. Most digital meters, and oscilloscopes (check max volts are OK on the input first, these things are expensive) will satisfy this, as will quite a lot of analogue meters.

Oh, and if the voltage is high, watch out - I've given myself tiny shocks off these things...
 
nobbylon said:
after reading Olson's post about using vivitar 283's on his M8 I thought I would post this link,

http://www.botzilla.com/photo/strobeVolts.html
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I found this page the other day. I am trying to figure out if my Vivtar 2800 is safe to use with my Canon 20D, Yashica E35, and my Oly OM1. The differences in voltage readings are disconcerting at best though. For instance readings posted for the 20D range from 4V-170V. With about four other readings in between, therefore a No? was given for compatibility. Low batteries in either the voltmeter or flash? Is there a residual amount of voltage left after the initial firing of the flash that is being misinterpreted here that would result in a lower reading?
Stranger still my 20D has a TCV rating of 250V, not gettting its xsync signal through the shutter(@6V). I have not had a chance this weekend to break out my multimeter and play, maybe this evening.

BTW, sync filters are always an option if the voltage is to high.
 
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Daaris,
for me I would feel ok about using it on an OM or the yashica but I wouldn't use on the 20D. after reading more about this I'm now going to stop using my 283 on my D70.
Far better to get a later compatible flashgun than mess up a nice camera.
I did read somewhere about someone frying a Leica R4 with an older flash so better safe than sorry,
regards j
 
nobbylon said:
Far better to get a later compatible flashgun than mess up a nice camera.
Click to expand...

Yes, I agree. Aside from what I posted, I have still been reluctant to use my Vivitar with my dslr. Your opinion further confirms this, what a silly, expensive loss just for a flash.
 
I use one of my old 283's on my Pentax istD with a wein safe sync, works fine. The old Vivitars had voltages over 300 volts, they work fine on older cameras with mechanical sync contacts but be careful with digital cameras.
 
Wouldn't it be nice if there were standards? It kind of sounds like Canon is the worst offender in the camp of camera manufacturers that produce cameras that won't stand up to 'normal' or ISO compliant flashguns. On the other hand, flashguns seem to come from all over the map in terms of voltage, and most manufacturers are 'guilty' of producing units outside of ISO compliance.
I am beginning to feel lucky that my digital camera (Pentax std-s) has withstood hundreds or thousands of frames shot with my older flashguns (Vivitar 285 HV's)!
 
The Wein Safe-Sync will reduce the voltage presented to the camera terminals from roughly 400V to about 6V. In the Safe-Synch, you don't actually trigger the strobe directly, but through an electonic component which acts as a switch which isolates the flash from the camera terminals.

Virtually all older flashes have the same (cheap to make) setup which has been used for years. Though I have never heard of or confirmed damage, it could be enough of a concern that using a newer unit with lowered trigger voltage or the Safe Sync is probably a good idea.

Use your older units as slaved off-camera units, keeps the old stuff alive and working. Vivitar 283's and 285's are still banging away daily in studios all around. The 283 came out in 1973! Were still being sold as late as 2005 or so, new. Vivitar discontinued them finally because the molds literally wore out and could not be patched any longer, that's the story, at least!
 
One way of dealing with old high-voltage strobes is simple: get a flash trigger and receiver so that there is no contact between the camera and the flash at all. I have one of the tiny new gadgets (not the old "Cactus" design failures), and they work fine with low and high voltage flashes. The ones I tested have more than 200 volts. For a set with two receivers I paid just 33 dollars... 60-100 feet range, and reliable.
 
The older "Made in Japan" Vivitar 283 do have a high Trigger Voltage but the newer ones may have a more normal voltage (somewhere around 6 volts)
I have three of the older ones and don't use them on my newer gear but then most of my stuff is of the older gear...
To be sure one must check each and every one...don't take any chances...
 
I don't know about others but the Nikon D200 can easily handle trigger voltage up to 250v.
 
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