Disabling pre-flashes on GF3

Discussion in 'Lighting Forum' started by gsk3, Feb 24, 2013.

  1. gsk3

    gsk3 Mu-43 Regular

    Jan 29, 2012
    I just pulled out my old Strobist gear (well, it was before there was such a thing as the Strobist blog, but same idea) and tested it with my GF3.

    I've got an Achiever 632T connected to a Wein peanut slave. The flash is properly triggered by the GF3's built-in flash (I can see it fire), but only the faintest of glows is visible in the picture, and the overall exposure is pretty low. I assume this means the pre-flashes are triggering the peanut prematurely, causing the camera to think there's more light than there actually is, and then by the time the camera actually fires the glow from the remote flash has mostly faded.

    So how do I turn off pre-flashes in the GF3?
  2. JJJPhoto

    JJJPhoto Mu-43 Veteran

    Jul 8, 2011
    Cincinnati, OH
    Real Name:
    Jerry Jackson Jr
    On "most" cameras there is no way to disable the pre-flash on the built-in flash.

    Do you have the Wein "PN" or the "PND" peanut slave triggers? The PN will fire as soon as it sees the pre-flash but the "PND" will ignore the pre-flash and fire the off-camera flash only on the exposure flash from your built-in flash.

    You can also find other "digital" optical slave triggers that ignore the pre-flash and only fire on the exposure flash.

    Amazon.com: Morris DS-1 Digital Slave Trigger with Hot Shoe Mount.: Camera & Photo
  3. gsk3

    gsk3 Mu-43 Regular

    Jan 29, 2012
    It's the PN unfortunately.

    I guess I'm in for another $30 :-/

    Thanks for the info. Kind of amazing this can't be fixed in firmware (but then again, there's no flash exposure compensation on the GF3 either, which should just be a firmware fix). Woe.
  4. nsd20463

    nsd20463 Mu-43 Regular

    Apr 30, 2011
    Santa Cruz, CA
    You should try setting the external flash to half power or less. That might give it enough charge to flash twice in quick succession.

  5. twalker294

    twalker294 Mu-43 Top Veteran

    Aug 18, 2010
    I am using a Wein peanut slave to fire my Vivitar 544 with my OM-D. On my camera, if you set the flash to manual power it only pops once. This makes sense since the preflash is used to meter the scene. If you set the power manually then there is no need for the flash to meter -- it will just fire at the power you set. I set mine to the lowest power, which is 1/64, and it fires my external flash without contributing any light to the scene.
  6. gsk3

    gsk3 Mu-43 Regular

    Jan 29, 2012
    Interesting. So I guess the next question is if the GX-1 behaves the same way, as that was my next likely camera upgrade (and $30 + $7 shipping for a trigger that ignores pre-flashes is 1/6th the cost of a GX-1 these days!)?
  7. inkista

    inkista Mu-43 Veteran

    Jan 13, 2012
    San Diego, CA
    Yes. If you CAN set your pop-up flash to manual, vs. TTL, then there will be no preflash, and you can trigger a first-burst optical slave.

    Or. If you dial down the power on the flash, it may be capable of recycling quickly enough between the pre-flash and the main burst. My Nikon SB-26, as long as I used it a 1/2 power or lower settings was able to do this with its built-in optical slave, which surprised the heck out of me.

    This is just me, but I'd actually recommend considering a cheap Chinese Yongnuo manual flash like the YN-460ii or the YN-560 (or 560ii), since they have built-in optical slave modes, one of which is immediate on the first burst, and one of which can ignore a pre-flash.

    Or. Just blow the $30 on a set of cheap radio triggers instead like the YN-602s and free yourself from line-of-sight requirements, and increase the reliability and range of your triggering. :D Srsly. There's a reason we like radio triggers for Strobist work.

    Don't get the YN-603s, though. There's a fit issue with mft hotshoes.