TTL Passthrough for on-camera TTL flash: unable to adjust flash power + zoom?

edited July 2017 in V6 II Problems

I have the latest firmware FUJ.1.001 on Cactus V6II.  What I want is the ability to shoot TTL flash on camera.  

Here are my setup steps:

1) Mount v6ii on Fuji X-T2 camera and lock
2) Mount Canon 580EX on top of v6ii and lock.
3) Turn on camera
4) Turn on 580ex.  Set flash mode to ETTL and flash zoom to 70mm in Manual.
5) Switch V6II on TX mode.  Turn on TTL for group A. Set "TTL Passthrough" ON, Exposure Lock to "Flash Compensate" (FEC). 

I then took few shots at ISO640, 1/50s, f/2.5.  Flash seems firing properly.  To be sure, I try to change f/stop on the lens and when I half-press camera button, the new f/stop does display accordingly on the flash, which tells me TTL seems working.  See my snapshots.

Next, I would like to use V6II to remotely adjust the flash power and flash zoom.  

However, when I try to press OK button to toggle between power & zoom and turn Selection Dial wheel to adjust power and zoom, they don't work at all meaning the photos taking before and after changing these options remains identical.  Is this a bug or expected?  I know these controls work properly while V6II acts as commander for off-camera flash, why don't they work in this TTL passthrough?

I finally figure out to change power (FEC) via Pressing + holding Menu button while turning Selection Dial to do adjustment and that works properly.  However, this requires two-hand operation and completely stop me from shooting.  

I hope I'm missing some instructions and so please help.  But if this is a known issue, I hope they will be addressed soon as shooting on-camera TTL flash in door is as important for my work as shooting off-camera flash.

Many thanks. 


  • edited July 2017
    I don't think you are missing anything.

    With a V6II you can essentially control five groups: Four off-camera groups and one on-camera group/flash.

    The four groups A-D you see in the standard display are all for off-camera flashes. You might be asking for a way to (re-)assign one of the standard groups to on-camera flash control, but with the current V6II that's not possible.

    A potential workaround might be to just use the controls of the on-camera flash.
  • edited July 2017
    Interesting analysis (thanks Class A!).  I think the display when I press + hold Menu button is for on-camera flash, which is very cumbersome.  V6II should be smart enough to automatically override group A for on-camera flash display when TTL passthrough mode is ON.  Then, all flash controls can be adjusted via OK button + Selection Dial with one hand. 

    As of now, this TTL feature works but in a very limited fashion.
  • Thanks for your suggestion, @timelessfoto. I have passed to R&D for consideration.
    Antonio Lao
    Brand Manager

    To help us better help you, always state the exact firmware version installed on your Cactus device(s), such as: "1.1.013", "NIK.A.001", "v.103", or "A06".

    TTL or HSS not working on Cactus V6 II and V6 IIs? Be sure to check hot shoe connectivity by doing the <CAMERA INFO> check.

    Feel free to suggest an improvement or share product ideas. Contact us directly at  At Cactus, we listen. 
  • sure, thanks for listening to our feedback, Antonio.
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