Remote flashes flicker violently when I half-press shutter on Canon 5D3 if using TTL pass through

Hi - I just bought 4 new Cactus V6.

I have a Canon 5D3 with a Cactus V6 in the hot shoe and a Canon 580 EX2 flash on top of that.  I have the Cactus set to TTL pass through.  I then have 3 Canon 430EX flashes attached to three remote Cactus V6's.

If the 580 flash is turned off then everything works fine.  However, if the 580 flash is turned on then when I press the shutter half way to focus the three remote flashes go crazy -- rapid firing on their own, very fast more like a very bright flicker.  The green LED on the V6 that is sandwiched between the camera and the 580 flash also starts strobing in sync with the erratic rapid firing of the remote flashes.  It does this 100% of the times I try.

Troubleshooting instructions for "Flash Misfire - Unexpected Flash Firing" gives the following possibilities:
1) poor hot shoe connection. - I redid connection and all seems fine.
2) background radio interference - I get this regardless of where I am.  I also tried changing channels.
3) Tx and Rx are too close together - I get this at any distance.
4) Optical trigger switched on. - It is turned off.


  • Helllo @Mike4371

    That's indeed very erratic and unheard of so far. What firmware are you running on your V6?

    To check, press and hold Group A + D buttons as you switch on V6 to either TX or RX mode.

    Thank you!
  • V1.1.016
  • Thanks @Mike4371

    Please try the latest 1.0.019 and see if it helps?
  • The problem is fixed.  I updated the firmware and that did nothing.  I then noticed that I had properly configured the three V6's in RX mode to use the proper 430EX profile, but I had never entered a profile for the V6 that was on the camera in TX mode.  I configured it to the 580 EX2 flash that is mounted on top of it and suddenly everything is fine!

  • Great news!  Thanks for letting us know @Mike4371 :)
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