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Thread: Syncing non-digital flash with DSLR via slave

  1. #1

    Default Syncing non-digital flash with DSLR via slave

    I just discovered today, that if I mount my Vivitar 185HV on a handle mount, with an optical slave and trigger it off with the in-build 10D flash set at -2 stops, no matter what shutter sped I use (down to 1 sec), I simply can't get the flash to sync with the shutter. Also tried conncting the slave via cable to the flash, and triggered it using the in-built flash. Niente. No goh. Buay Sai sync.

    Did anyone encounter this before, and what are all the possible ways if I want to continue using my non-digital flash off-camera?

    BTW, when I mount it in the hotshoe as normal, it syncs fine, but besides wanting an elevated angle of light, I'm afraid of frying my 10D.

    Any opinions...any Electronics Engineers out thre can help, please?

  2. #2

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    The reason why it doesn't sync is simple. PRE-FLASH. The built in flash will pre flash once, and that will fire off the optical trigger.

    dunno about the rest tho.

  3. #3
    vince123123
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    perhaps you can try using an IR trigger /slave flash mounted to your camera to trigger the vivitar. alternatively, use a pC sync to hotshoe convertor and connect it to your vivitar

    Quote Originally Posted by Feinwerkbau
    I just discovered today, that if I mount my Vivitar 185HV on a handle mount, with an optical slave and trigger it off with the in-build 10D flash set at -2 stops, no matter what shutter sped I use (down to 1 sec), I simply can't get the flash to sync with the shutter. Also tried conncting the slave via cable to the flash, and triggered it using the in-built flash. Niente. No goh. Buay Sai sync.

    Did anyone encounter this before, and what are all the possible ways if I want to continue using my non-digital flash off-camera?

    BTW, when I mount it in the hotshoe as normal, it syncs fine, but besides wanting an elevated angle of light, I'm afraid of frying my 10D.

    Any opinions...any Electronics Engineers out thre can help, please?

  4. #4

    Default

    Can I switch off the pre-flash using custom functions?

    I don't want to have the 285 connected in any way to the cam body, unless there's an adapter that REDUCES the trigger voltage.

  5. #5
    Senior Member denniskee's Avatar
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    Yes, if you use a manual flash with optical slave trigeering device, the pre-flash from the EX series (ETTL & ETTL2) will trigger the manual flash. Than it will not be able to charge fast enough to fire again in split seconds when the main flash from the EX goes off. There is a detail writeup on Canon flash system in the photo.net.

    To overcome this problem :
    Switch your EX series to manual mode by the "mode" button. Although the auto zoom still works, it will basically function like manual flash. Its slower to use since you will need to check the distant covers by it when set to certain aperture. If it is too strong, than use FEC on the flash or the camera, depending on your preference.
    photography makes one sees things from all angles.

  6. #6

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    Hey thanks for that info Dennis!

    I went and got a Metz 54mz 4 to help overcome th problems I was facing, but would certaily keep the info you provided in mind the next time I try to sync multi flash set-ups!

    Compliments of da Season!

  7. #7

    Default

    What I do is to fire off the preflash by doing a FEL. That should get rid of the preflash.

    However, if your slaves are on during FEL, they will fire off too. Then you will have to wait for the slaves to recycle before you do the actual flash shoot.

  8. #8

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    One way is to use a cheap external flash on the hotshoe as the one to trigger off your slaves, rather than the built-in flash. That will take care of your pre-flash.

    I'm sure you've seen this list of flash trigger voltages:

    http://www.botzilla.com/photo/strobeVolts.html

    If you like, you can measure the flash trigger voltage of your flash yourself. Instructions can be found here:

    http://www.botzilla.com/photo/g1strobe.html

    A voltmeter can be bought for about 10-20 bucks from Sim Lim Tower.

    After messing around with these solutions, I finally got a couple of 420EX's and an ST-E2 wireless trigger. A very good solution since you get E-TTL and can adjust the ratio of each flash without having to do any manual compensation for flash output. And of course don't have to worry about frying your flash trigger circuitry.

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