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  1. #21
    Steve Smith's Avatar
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    Quote Originally Posted by RalphLambrecht View Post
    Steve

    Would it help to connect the voltage meter to the flash contacts with, let's say, crocodile clamps, and then, give the flash time to charge up before taking a reading?
    If you connect a meter up then turn it on, you will see the sync. voltage rise as the main HV supply charges as it is usually derived from this supply.

    Another thing to keep in mind is the internal resistance of the meter you are using will have some effect.

    e.g. if the circuit is as I have already described with a 1M resistor supplying the current to charge the sync. capacitor then if you had a meter which had an internal resistance of 1M, it would show a reading of half the actual voltage.

    Modern meters have higher internal resistance and one with a value of 10M would show 90% of the actual voltage.

    My old AVO 7 moving coil meter however has quite a low resistance. I don't know what it is but it is enough to fire the flash! (Vivitar 285).


    Steve.
    Last edited by Steve Smith; 01-05-2010 at 02:08 AM. Click to view previous post history.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  2. #22
    Steve Smith's Avatar
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    Quote Originally Posted by RalphLambrecht View Post
    2. I'm looking at ISO 10330:1992. It limits electronic flash trigger voltages to 24 V and sets this value as the camera minimum.

    Any thoughts?
    Lots of flashes were made before 1992 and in my opinion, a camera designer should take account of that and make sure his product is compatible.

    As far as ISO 10330 is concerned. The logical way to handle it is to set all flash voltages low but make the camera compatible with a much higher voltage - just in case.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  3. #23
    RalphLambrecht's Avatar
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    Quote Originally Posted by John Koehrer View Post
    Older studio flash could hit that 250V threshold no problem.
    Which one? There are none on this exhaustive list. My old Speedotron has a trigger Voltage of 68 Volts, and I would not hook it up to any of my cameras, analog or digital. Carl Zeiss told me that their Hasselblad lenses can live with that Voltage for some time but will wear over time. Nikon in Germany told me to stay below 5 Volts for their digital SLRs.
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  4. #24
    Mike Wilde's Avatar
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    I tend to play it safe, and order little hot shoe optical slaves with a PC socket on the side off the *bay from Hong Kong for use with some of my older potatoe masher type flash units with pc synch leads. They cost no more than $15 including shipping and taxes, and tend to last about a year before the high voltages I plug into them tend to cook them off and they stop working.

    I trigger these slaves with a small low synch voltage flash on the senstitive camera, with a piece of black e6 film taped across the flash window on the camera, since this film passes the IR that the slaves need to trigger, but not the on camera optical output that I am usually trying to suppress when shooting with multiple flashes for portraits etc.

    I run an old Metz 60CT2 that synchs at about 380 V per measurement with a 10Mohm digital VOM, and a Braun Hobby EF300 that synchs the same at half power, and closer to 580V at full power. Both these head and pack flash sets offer a guide number that is 180 in feet, so they are useful for firing into umbrellas and soft boxes and still have worthwhile amounts of light coming out of the modifier for shooting meduim format portraits at the likes of 160iso and f/8.

    If I need more light and there is AC on the location I haul out the Speedotron Blackline pack fitted with a Wein HSS, and its associated heads.

    But it is nice to be able to do on site work with 'just' a case for the camera, another for the pack flashes and trigger flash and flash meter, and a case for the light stands, modifiers and tripod. This can fit into the back of my wife's compact car. The Blackline set comes closer to filling the back of my pickup truck, but then I have enough light to fill a whole theatre if need be.
    my real name, imagine that.

  5. #25

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    Quote Originally Posted by RalphLambrecht View Post
    Which one? There are none on this exhaustive list. My old Speedotron has a trigger Voltage of 68 Volts, and I would not hook it up to any of my cameras, analog or digital. Carl Zeiss told me that their Hasselblad lenses can live with that Voltage for some time but will wear over time. Nikon in Germany told me to stay below 5 Volts for their digital SLRs.
    How's about the old Ascors from the '70's?
    Heavily sedated for your protection.

  6. #26
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    I bought a Wein Safe Sync http://www.bhphotovideo.com/c/produc...t_Shoe_to.html that reduces the trigger voltage of any flash to below 6Volts I can use my Metz 60 CT1 whose trigger voltage is over200, and my Elinchrom studio flashes with my Canon T90 without frying the electronics.
    Last edited by benjiboy; 12-12-2010 at 12:53 PM. Click to view previous post history.
    Ben

  7. #27

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    From the botzilla list there are quite a few at 200V+, some at 270V.
    Heavily sedated for your protection.

  8. #28
    CGW
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    Older Nikon AF flashes like the SB24/25/26/28 are very affordable now--no worries about incinerating your camera's electronics, either.

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