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GX7 pop-up flash as master> external flash as slave

Discussion in 'Panasonic Cameras' started by Frankgr, Nov 23, 2015.

  1. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
    I have bought a NIssin i40 as an off-camera flash for the GX7 (wire-less). It is optically triggered by the pop-up flash. But I do not want the pop-up flash to illuminate the scene.
    I see that i can set 'communications light to low' but that still allows the pop-up light to show in the scene.
    I understand that it's possible to place an Infrared (IR) filter over the pop-up. But I can't find one in gel form.
    Someone suggested a developed, but no image on it, piece of slide film (transparency)?
    Can I use a gel ND filter?
    Anyone else done this before?
    Thanks
     
  2. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Hi,
    You could get a radio trigger.

    Barry
     
  3. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
    Thanks. I am aware of that option.
     
  4. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    OK...
    ND is probably going to be too dark.

    You could get a small glass IR filter and remove it from the housing (as was done with another filter at Milky Way )

    Barry
     
  5. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
    thanks I'll look if there's a ir filter nearby (Toronto area)
     
  6. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    Sure. I have a cheapie flash that I often use as a trigger. It's a bit of a balancing act to get enough trigger light but no noticeable photo illumination. The balance can be different for every lighting setup, too.

    There is no need for anything fancy. First step is to make sure that the trigger sensor of the remote flash can directly see the trigger flash. Some black electrical tape can block a portion of the trigger flash lens. A piece of white paper attached with Scotch tape can cut the flash strength. Some masking tape ... Really, anything that can be adjusted to reduce the light intensity can work. My main light blocker for my little flash is a piece of 1" wide white nylon webbing, attached with Velcro. No need for anything fancy. In some situations, you might have to increase the power of the remote flash reduce the exposure effect of the trigger flash,.

    RE IR, I never thought of it. I guess the first step is to see whether the remote flash will trigger if it gets an IR pulse. Maybe Nissin can tell you.
     
  7. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
    Thanks.
    I'll send nissin an email now to check.
    So far it seems difficult to find a very small IR filter anyway so I may need to just cut the pop-up flash light with something and try to still get the remote to 'see it'
     
  8. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
  9. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
    Great. Thanks!
    I was concerned about taping the pop-up flash. I don't know until I receive the flash (next week)how direct a line of sight the external flash has to be with the pop-up for optical triggering. And also how dim/blocked/taped the pop-up can afford to be.
    Slightly off topic, but very related, would the on-camera Flash Exp Compensation (front dial) affect only the on-camera flash, or the off camera flash, or both. The camera flash would have been set to RC (remote control)
     
  10. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    Well, if you want your trigger flash to be as dim as possible, the sensor on the slave will have to see it directly, not as a bounce. Needed light intensity from the trigger will depend on the distance to the slave. Same as any flash situation: Double the distance to the slave, the trigger light goes to 1/4 intensity, so you'll have to open up the tape until the slave triggers again.

    I have no idea. I never use that fancy stuff because I'll never use it enough to become really familiar with it. I think you're going to be all manual anyway, so the exposure adjustment is with the aperture setting.

    :2thumbs:Radio triggers really are nice! I hardly use my trigger flash any more.
     
  11. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
    Thanks
     
  12. piggsy

    piggsy Mu-43 All-Pro

    Just want to double check something here - never used the panasonic menu, but going from the advanced manual, do you have the onboard flash set to 'off' in the wireless setup menu rather than 'ttl'? The flash can still send command signals if it's set 'off', and it's a separate setting from the wireless communications strength. From using the LM2/E-P5's inbuilt flash I really have to work to get them to show up in a shot if they're "off" (eg something really reflective really close).
     
  13. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
    [QUOTE="piggsy, post: 834699, member: 22045"...do you have the onboard flash set to 'off' in the wireless setup menu rather than 'ttl'? The flash can still send command signals if it's set 'off', and it's a separate setting from the wireless communications strength.[/QUOTE]
    Wow. I did not know that it can still send a signal when it's off. But if it's set to 'off' why are the variable settings still available for wireless communication strength.
     
  14. piggsy

    piggsy Mu-43 All-Pro

    You can vary the signalling strength to other devices in case their IR receiver is far away, at an angle to the command flash, or there are going to be competing signal sources (bright sunny day, hot lamps, whatever). Another factor is as I mentioned before, if you're shooting something very reflective or very close, the stronger signal flashes can still show a bit of flash glow after the signal's fired. The actual exposure-contributing flash happens after the signal and test metering for TTL.

    jx0GCQv.

    Download Panasonic Lumix DMC-GX7 Operating Instructions For Advanced Features
     
  15. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
     

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  16. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014
    I did not see or understand that before. Thanks for pointing it out (p225). So by switching off the firing of the flash in the menu, the communication light setting in the menu can be be used without worrying much about the pop-up flash 'lighting' the scene or affecting exposure under 'normal' conditions - not very reflective or very close ones?
     
  17. Frankgr

    Frankgr Mu-43 Regular

    43
    Oct 18, 2014

    I guess that even if one finds a way to prevent the camera flash from affecting exposure, the main issue (for me) would be the distracting/disturbing pulsing of the pre-flash / control signal, on a a portrait subject.

    Indoors, at least I can tilt the camera flash t the ceiling. Outdoors in harsh noon day sun...I dunno.