TTL pass-through gets confused

Hi there,

I have been using a few V6's for a few months now. My setup is a V6 on a Canon 5D Mk3 and either a 600ex or 580ex 11 on top of the V6 (on camera) and TTL pass-though enabled. 

I initially had some weird behaviour and found that if I set the flash back to ETTL everything works fine. I can then happily shoot for a long time and all is good, but sometimes, and this has happened regularly, the TTL pass-through gets confused and starts emitting more flash power than it should. For example I may be shoot with +0.8 flash exposure compensation, and suddenly the images are a lot brighter. To resolve the issue I have to remove the flashgun, turn off the V6, fit the flashgun again and turn on the V6. 

So bottom line is something is going wrong with the TTL pass-through over time. 

Any comments would be appreciated.



  • Hello David,

    When using the V6 with Canon flashes in TTL pass-through mode, please select the flash profile to Canon flash according to the flash mode. If not, the TTL pass-through may not function properly.

    BYW, have you updated your V6 to the latest firmware? To check it, please press and hold the A + D button, then switch it to either TX or RX mode from Off position. The firmware version will be shown on the display.

    Hope that helps!

    Ray Chan

    Senior Product Specialist
    Harvest One Limited
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