Remote Slave Flash trigger probs.

Discussion in 'Australia Photography' started by Rod Out Back, Aug 3, 2006.

  1. Rod Out Back

    Rod Out Back Guest

    Folks,

    I have 2 of those Nissin flash slave units that detect the camera
    flash firing, and trigger in sympathy. Well...they're supposed to do
    so!


    I have an old Vivitar flash (550FD)that doesnt seem to work at all
    using the remote slave. Turns out it doesnt work on the other slave
    unit either. I just wrote this one off as a crook flash.

    Flash has a trigger voltage low enough for digital cameras (I checked
    with multimeter), but doesnt seem to want to fire on the slave.

    However, I can use this flash on my Panasonic FZ-30 without any
    problems. I can also use the Canon Speedlite on the FZ-30 as well. The
    Panasonic shoe has no higher functions than simple trigger, but both
    flashes work fine on the camera.

    Turns out the Canon flash Speedlite 380x works on either slave unit,
    but I came across something weird. When I was just holding the slave
    flash(380x) while triggering the camera flash, the slave would only
    fire once before refusing to fire again. I would have to physically
    disconnect before it would fire from the slave again.

    However (and this is where it seem to have gotten a bit strange), I
    screwed the Canon(and attached slave unit) onto my tripod, and the
    damn thing works all the time. Every flash from the FZ-30 fires it...

    Is there any chance the Vivitar has a slightly higher threshold
    trigger than the slave flash unit is prepared to give?

    Most times I wont need both flashes, but I'd like to experiment with
    light sources away from the camer. I have what seem to be 2
    functioning flashes I could use as slaves, but one doesnt seem to
    trigger.

    Anyone got any ideas or thoughts? Anyone had much experience with
    these slave units?


    Cheers,

    Rod.....Out Back
     
    Rod Out Back, Aug 3, 2006
    #1
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  2. Rod Out Back

    Nemo Guest

    Most slave units will not work with digital flash because digital flash
    has pre-fire which triggers the flash, (or not) out of synch with the
    shutter of the camera.

    A Metz 34cs2 slave flash for example has three settings. Manual, slave,
    and slave with pre-fire depending on the flash unit of the camera you
    are using.

    A Fuji digital camera will trigger a normal slave flash, a Nikon won't.
    I know that from my own personal gear.
     
    Nemo, Aug 3, 2006
    #2
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  3. Rod Out Back

    Pete D Guest

    Annoying that. My Pentax DS and Sony V1 allow me to turn off the preflash
    (usually used for redeye reduction) and fires my Sigma DG 500 Super
    perfectly.
     
    Pete D, Aug 3, 2006
    #3
  4. Rod Out Back

    Rob Guest

    Come on! Analogue it must be then.


    Pre flash is for red eye reduction.
     
    Rob, Aug 3, 2006
    #4
  5. Rod Out Back

    Noons Guest


    Where does one get those nowadays? The robot - sorry - attendant
    at the local camera shop doesn't even know what the heck I'm talking
    about and it's been a while since I last saw one on epay!
     
    Noons, Aug 3, 2006
    #5
  6. Rod Out Back

    Rod Out Back Guest


    Cant remember - Online store in Australia late last year. I also
    picked up a macro ring flash that works well (aside from not being
    TTL).

    I'll dig around and find the link, I you like.


    Cheers,

    Rod.....Out Back
     
    Rod Out Back, Aug 3, 2006
    #6
  7. Rod Out Back

    Nemo Guest


    From - http://www.srelectronics.com/



    Why Do You Need a Special Flash for a Digital Camera?

    Most popular digital camera lines have inadequate flash systems and lack
    a connector for use with an external flash. Ordinary slave units will
    not work with most digital cameras because these cameras use a very
    rapid series of pre-flashes
    reduction).<<<<<<<<<<<<<<<<<<<<<<<<

    The pre-flashes are used to set the white balance of the camera's image
    sensor chip - not the exposure. A typical slave unit will fire on the
    pre-flash it senses while the digital camera captures the image on the
    last flash. Thus, the extra light from the slave does not show up in the
    digital camera photo.


    Here endeth the lesson.
     
    Nemo, Aug 3, 2006
    #7
  8. Rod Out Back

    Poxy Guest

    Why would a camera need to do a pre-flash to determine the white balance?
    Surely it knows exactly the colour temperature of its own flash?
     
    Poxy, Aug 3, 2006
    #8
  9. Rod Out Back

    Rod Out Back Guest

    Well, I dont seem to get one flash to fire at all from the slave
    unit(s), rather than firing early. It doesnt seem to trigger at all.
    As I said originally, the problem seems to be the slave unit not
    triggering one of the 2 remote flashes. Doesnt matter which slave
    unit, but for the same flash.
    Hence I wondered if one flash might have a higher trigger voltage than
    the slave unit can supply. A bit weird, as I understand that the
    slave unit simply closes a connection to trigger the flash.

    The camera (Panasonic FZ-30) has a simple flash shoe on it (where I
    mentioned that I can fire both flashes properly on the camera, albiet
    not using any TTL flash functions).

    I havent noticed any pre-flash occuring(as a number of digital cameras
    I have used do) from the flash on the Panasonic. It might be that
    I've got the camera flash set to operate as on fully, rather than
    red-eye reduction.

    Thanks anyway, but I suspect the problem lies more with the flash
    unit, rather than the slave. For some reason, the Vivitar 550FD
    doesnt seem to trigger using the slave.


    Cheers,

    Rod.....Out Back
     
    Rod Out Back, Aug 4, 2006
    #9
  10. Rod Out Back

    Mr.T Guest

    Actually some camera's also use preflash pulses for communicating with their
    own slave flash units, or setting autofocus.
    There are digital slave triggers that can be set for the number of pre flash
    pulses to ignore. Some will even calculate it for you automatically by
    simply firing the camera flash once.

    MrT.
     
    Mr.T, Aug 4, 2006
    #10
  11. Rod Out Back

    Rob Guest

    Would the duration of the flash be sufficient to allow auto to focus?
     
    Rob, Aug 4, 2006
    #11
  12. Rod Out Back

    Mike Warren Guest

    Rob wrote:
    <snip>

    How's the hand?

    -Mike
     
    Mike Warren, Aug 4, 2006
    #12
  13. Rod Out Back

    Rob Guest

    Hasn't fallen off yet. The Doc looked at it on Wed and said it was OK -
    just keep it dry and covered, then the bandages went back on.



    r
     
    Rob, Aug 4, 2006
    #13
  14. Rod Out Back

    Mike Warren Guest

    That's good. It takes a while to grow a new one. :)

    -Mike
     
    Mike Warren, Aug 4, 2006
    #14
  15. Rod Out Back

    Mr.T Guest

    ....
    Presumably so, since that's what many of the built in flash camera's do.
    Canon provide an option to turn it off when using an external flash with IR
    auto-focus assist. Probably others do too I guess. The manufacturers can
    probably provide more detail though.

    MrT.
     
    Mr.T, Aug 5, 2006
    #15
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