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All About Flash Triggers

What is a “Flash Trigger” and why would I want one?

A flash trigger is a device that allows you to trigger an external strobe using its own source of light rather than utilizing a camera flash or an electrical signal.  Some flash triggers use traditional flash tubes, but many are now utilizing very energy efficient LEDs.  Flash triggers may also be fully manual or incorporate a TTL Converter circuit.  The flash trigger uses a small pulse of light to fire a compatible strobe in sync with the camera shutter.

Flash Triggers for underwater housings are currently being manufactured by Nauticam, Sea & Sea, Subal, and Underwater Technics, plus more in development.  Some of the flash triggers are enclosed in finished shells, others are bare circuit boards with exposed LEDs.  The form is largely irrelevant to performance– they all are designed for a similar goal: Improve a camera’s performance in an underwater housing while simplifying strobe triggering.

Note that sometimes these devices are called TTL Converters or Optical TTL Converters, and some of the devices provide only electrical conversion and not optical triggering.


Benefits of flash triggers:

  • Light-weight
  • Do not require an electrical bulkhead
  • Allow the use of light-weight fiber optic cables
  • Can trigger as rapidly as the camera can shoot – even incontinuous
  • Some provide TTL conversion technology
  • Prevent additional o-ring maintenance required by electrical sync cords
  • Are very reliable
  • Use less camera battery power than a pop-up flash



  • Not every strobe is compatible with every flash trigger
  • Older housings may not have a flash trigger solution
  • They require batteries (though many will allow a set of batteries to last for years)

Making the switch

If you are still shooting electrical sync cords or the pop-up flash on your camera takes too long to recycle, or you are looking at upgrading to a newer camera, it may well be time to consider a flash trigger.  The cost is not much more than that of buying electrical bulkheads and sync cords and once you switch, you are not likely to ever go back.  So what type should you choose?

The first thing to check is what is available for your camera and housing.  The options are growing almost every month and the current options can be seen below.  If you shoot strobes manually, you may only need a manual flash trigger which are often more economical than those with TTL conversion circuitry.  Nauticam has started shipping certain camera housings with a manual flash trigger installed as standard equipment (NA-D5 & NA-D500) and manual flash triggers are available for many existing models of camera housings at very economical pricing.

Recently, flash triggers with TTL conversion capability have come on the market and provide an exceptional solution for those who enjoy the convenience of TTL, but want the light weight and better overall performance of a flash trigger.

Whichever type of flash trigger you choose, the experience will be a refreshing change from traditional technologies.  Whether enthusiast or pro, optically triggered strobes are becoming the standard.