Sea & Sea Optical YS Converter

Overview & Benefits of Sea & Sea's New Built-in TTL Converter
By Brent Durand


Sea & Sea Optical YS Coverter

Overview & Benefits of Sea & Sea's New Built-in TTL Converter

By Brent Durand




Sea & Sea has a new Optical YS Converter available for their latest housings, including the MDX-70D and MDX-D7100.  It’s a great option that many divers will want to add on to their system, but what is it?  What is TTL and what does this new converter do?

There are two ways to shoot with strobes: manual power adjustments or TTL (auto) power. Some photographers shoot manual all the time, some shoot TTL all the time and some shoot TTL in some situations and manual in others. Below we discuss the benefits of Sea & Sea’s Optical YS Converter and what they mean.


Key Benefits


Optical – No Need for Sync Cords

Sea & Sea’s Optical YS Converter converts the electronic TTL signal into a light signal. This is good for two reasons. First, photographers can use fiber optic cables instead of sync cords. These are smaller, more reliable, cheaper, easier to maintain and will not flood (sync cords can flood at strobe or housing bulkhead end and require daily o-ring maintenance).

The second benefit is that photographers can use fiber optic cables (light signal) without using the camera’s internal flash, since the Optical YS Converter converts the electronic signal into a light signal. Rapid firing of strobes with fiber optic cables was previously limited to the recycle time of the camera’s built-in flash, but this is no longer an issue. It was one of the key benefits to using sync cords over fiber optic cables, so I predict sync cords to disappear once all housing manufacturers start using optical converters. Divers also save camera battery life by not using the camera’s built-in flash.

Left: 2x Sea & Sea Fiber Optic Cable II.
Right: Dual sync cord (Nikonos to Sea & Sea)


Change from TTL to Manual During the Dive

Another major feature of Sea & Sea’s Optical YS Converter is the ability to switch between TTL and Manual power with the press of a button. Divers must no longer commit to TTL or manual before the dive, instead choosing their strobe power mode depending on the current situation.


Switching from manual to TTL is easy mid-dive.


Blue LED means TTL is active.

Green LED means TTL is not active.


It’s Internal

No more bulky TTL converter dangling outside the housing. The Optical YS Converter is built into the housing, eliminating a strobe bulkhead and chances of it flooding.


Simply plug the fiber optic II cables into the ports - nothing is outside the housing!


Other Key Features

  • Fine-tune strobe power via EV controller on back of YS-D1, YS-01 or YS-110a strobe
  • Battery level indicator
  • Blue LED light indicates TTL mode is active. Green LED light indicates manual strobe power
  • Auto power off and easy re-activation to save battery life



  • Power:  2x AAA batteries (alkaline = 15hrs / Ni-MH = 12 hours)
  • Weight:  154g / 5.4oz
  • Housing Availability:  MDX-70D, MDX-D7100



The Sea & Sea Optical YS Converter is an optional (although highly recommended) accessory. If purchasing with a new housing, the team at Bluewater Photo can easily install it. For those adding it to their housing, installation is user-friendly, with two screws to attach the converter to the inside top of the housing.



So do you need the Optical YS Converter?  Different divers will have differing opinions, but with the accuracy of the converter and Sea & Sea’s new Fiber Optic Cable II, you’ll be kicking yourself for missing a shot you could have saved with TTL.

A great example is a light-colored school of fish that swam quickly by much closer than expected, blown out by your default “swim-around” strobe power settings. An optical TTL converter is certainly on my list to start saving for!



This review made possible with the support of



About the Author

Brent Durand is an avid California beach diver, photographer and writer dedicated to capturing unique underwater, ocean lifestyle and adventure images. Brent is editor-in-chief of the Underwater Photography Guide. Make sure to follow UWPG on Facebook for updates on everything underwater-photography.



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