Slave sensor flash timing

Discussion in 'Beyond the Basics' started by yegods, Nov 7, 2009.

  1. yegods

    yegods TPF Noob!

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    Hi all,

    I've bought a pair 1600W external flash units. I'm having trouble trying to get them to flash in time with my canon 1000d built in flash. When I take a photo they do flash but don't seem to make any difference.
    I have to use the built in slave sensors (triggered by the built-in flash) as I don't have a hot shoe flash. I've tried playing around with shutter times etc but they are still not hitting the mark. Anyone got any ideas on what I should be doing here.
     
  2. GeneralBenson

    GeneralBenson TPF Noob!

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    Ahh... You've been had by the old TTL preflash trick. It's gotten us all at one time or another. The flash on you camera, works in TTL metering mode, where it fires a preflash to help calulate the flash exposure, then fires again during the the actual exposure. What's happening is that the preflash is triggering your lights, then they are not recycled in time to fire during the real exposure. Unless your popup flash has a manual mode where you determine the intensity, and it only fire once during the exposure, then you'll have to find another way to trigger them. Option would incluse a sync cord and hot shoe adapter, an external flash which is on the camera fired in manual, or wireless trigger like pocket wizards and the like.
     
  3. yegods

    yegods TPF Noob!

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    Thanks for the quick reply GeneralBenson. I gues i'll have to get myself a hotshoe adapter to sync with these units. I have tried changing some flash settings where my build-in flash only fires one but I still don't get the result from the two External flash units. I've even tried taking a photo into one of the external flash units, it does flash but all I get is a photo of the bulb unlit.
     
  4. GeneralBenson

    GeneralBenson TPF Noob!

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    If you run a sync lead to one of the units, the other one will fire with it via the slave.
     
  5. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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  6. yegods

    yegods TPF Noob!

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    thanks Big Mike, I'll check it out. I live in Ireland so i'll probably have to pay tax and duties in i buy these from the US. I'll try a wired setup first just to make sure my strobes can do the job before investing further. Thanks again for the help and I'll let everyone know how I got on, which I think is only fair after their help.
     
  7. Big Mike

    Big Mike I am Big, I am Mike Staff Member Supporting Member

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    The cheap ones come directly from China (I think).
     
  8. KmH

    KmH Helping photographers learn to fish Supporting Member

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    Or get them off eBay.
     

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