16. Jul, 2017

Adding fiber optics to electric sync

Normally I avoid discussing technical matters in my Blog,  but here I make an exception for an old but still unresolved technical problem. It’s  about  implementing a LED trigger in  a camera housing/DSLR combo that is primarily designed for electrical  triggering,  with no facilities to trigger the strobes optically. In a way it is a follow up on my prior Zen blog about maintenance of your UW housing. Or even improving it! Some years ago I started a -seemingly never ending- discussion on this subject on the site ot Wetpixel,  which could be a sign  that  other people are also interested in solving the problem, or perhaps feel a bit annoyed why their ideas are not picked up by the manufacturers of UW housings.

Optical or electrical?   As repeated in many UW articles, LED triggers do not drain the battery and have less heat build-up than an internal flash.  The camera does not not have to wait for the pop up flash to recycle, meaning faster shooting, that  is as fast as your external strobes can handle or you buffer can take  (see also my earlier strobe review in the Technical section). For many years I have been using the Ikelite SLR housings designed for the Nikon DX series (D90, D7000, D7100 and D7200, respectively). The Ikelite-style bulkhead and plugs are widely recognized as the most reliable waterproof strobe sync connections available with superior TTL functioning. Still, the hazards of electrical connections interacting with seawater can never be complely ruled out. According to Murphy’s law  ‘anything that can go wrong  (corrosion, broken cables or connector pins, leakage)  will (one day) go wrong’.  Most tricky are small hidden defects like a worn out O ring or a slightly corroded contact that for years will  not cause any problems, but one day will definitely show up and cause a malfunctioning of your entire system. Which leaves shooting with ambient light as the only alternative for the rest of your diving trip.  With optical systems there  are no sync cables to flood or corrode or  connector pins that can break.  With a (working) optical LED trigger  in the Ikelite housing I would have the optical system as a back up, in case of malfunctioning of the electrical circuit.

How small can a LED trigger get? With Edward Murphy still bugging my mind, I have been scanning the internet for several years to find a small and thin LED trigger for my Ikelite SLR housing, so that my strobes would accept electrical as well as optical input. Although optical triggers are becoming more and more compact,  they  still  need a specially designed housing with enough space above the hotshoe.  Limited  space  above the hotshoe of my Ikelite SLR housing (less than 20 mm) not only  prevented its  internal flash to pop up,  but even to mount any of the available LED triggers.

As a  faithful reader of Peter Rowlands  UWP magazine,  I bumped on an  interesting  article in the recent issue nr. 97. It described another new gadget from a Hungarian based firm called  TRT electronics run by Balazs Kurucz.  Balazs recently added two new models of TTL Flash Triggers to his line of products.  Based on customer feedback and field-testing, they now  produced the i-TURTLE XS that is a thinner version of the i-TURTLE that allows for fitting into housings with limited space. This trigger is not wider than the 1 euro coin:  its size is only 35x25x13 mm. In fact it is the world’s smallest i-TTL adapter for NIKON systems. Another promising gadget could be the  Fantasea LED trigger, which is not only small but also  made to fit in various standard UW housings, and only needs 6.5 mm above the hotshoe. The Fantasea trigger is much cheaper than het TRT turtle trigger, but does not offer the TTL option in addition to manual triggering. The TRT trigger also alllows to use an electrical triggering mode via a switchboard in the housing.

Fitting the optical system After ordering the TRT trigger it appeared  to be not only incredibly small (see picture on top) but also to fit nicely on  the  Nikon D7200 hotshoe in the narrow space on top of the housing. The trigger unit on the hotshoe is connected via a cable with  the LED adapter. The two LED lights need then to be  be attached with some double sided adhesive tape on an empty spot  on  the lower frontal  dry side of the  housing, facing directly the cable insertion port on the wet side  to plug in the  fiber optic cables. An easy way to add fiber optic ports to almost any existing housing ito use a fiber optic mounting block  or universal mounting kit which can be purchased from UW dealers.

The following step is to find a way to make the strobes fire! The DS 161 strobes I use are great, but made for electrical sync cords. To make it function with optical cables you have to plug Ikelite’s 4401.1 optic adapter in the strobe. Even more important is to find an optic cable that is sensitive enough to transmit the signal  from the housing and make the DS substrobes fire. The cables I had used sofar on my Olympus PEN housing worked fine with an internal flash plus DS161/4401.1 adapter, but not with the mini LED trigger and LEDs in the Ike housing.  Only multicore cables seem suitable for LEDs.Some DIY photographers were also able to get their strobes firing with commercially available optic cable. Next month I shall inform you about the final steps that should lead to the solution I have been seaching for:  a working optical system in the Ikelite housing in addition to its electrical sync cables. So just hang on!