Canon Hot Shoe

My problem: trying to control scuba strobes from my new Canon G16.

I have ruled out optical control because my YS110 strobes work poorly in optical mode AND the G16 cuts out after about 20 onboard flashes in continuous burst mode. So now I am focused on wired sync control of my smart analog strobes via the camera hot shoe.

But I had a technology mismatch. The G16 hot shoe was capable of supporting either a dumb analog flash or a full featured Canon digital flash. The YS110 is a smart analog strobe, but capable of being operated as a dumb analog strobe.

Dumb is fine. My previous Sea & Sea camera hot shoe was dumb AND supported continuous burst mode. It would "fire" the strobe each time the camera recycled and captured a new image. It was dumb in that it would fire even if the strobe was not ready. The camera did not consider any feedback from the strobe. This worked fine since my strobes could cycle faster than the camera. No problems mate! Life was good.

The G16 hot shoe in analog mode is even dumber. Continuous burst mode is not supported in analog flash mode. The hot shoe X contact only fires once at the start of the burst in analog mode. Life is not so good. So analog control in continuous burst mode is a non-starter.

So let's do a quick review of the control of analog strobes based on the Nikonos protocol (I am not aware of any digital protocol scuba strobes). The strobe raises the X contact to 5 volts when it is fully charged and ready to fire. The camera shorts the X contact to ground when the shutter opens. If TTL is employed, the camera shorts the Q contact to ground when proper exposure has been achieved which instructs the strobe to stop discharging. Once the strobe has recharged it raises the X contact to 5 volts to indicate it is ready to start over. In dumb analog control the camera only has an X contact (it ignores the Q contact) and causes the strobe to perform a full dump on each shorting of the X.

The G16 does support continuous burst mode for compatible digital flashes. But this depends upon the flash knowing Canon's digital eTTL protocol supported via a proprietary Cannon hot shoe interface. There is a small number of compatible flashes. None are waterproof.

Time to investigate Canon's digital eTTL protocol?