Sunday, 20 February 2011

Sync cord end clip

Here's a little refinement after the initial test dive.

This clip allows the raw end of the sync cord to be fitted and removed underwater. This will allow much easier rolling out of the long cord now that the little hooked clip is not permanently attached.

The clip is stuck to the strobe by double sided tape.

I have also made up a short optical sync cord for use with a slaved on-camera strobe. This means I can just use a single electrical sync cord for the main strobe instead of the annoying double electrical cord.

Tuesday, 15 February 2011

Remote strobe underwater

So here's my first attempt.

The sync cord worked flawlessly, but it's so awkward dealing with 10m of coiled cable attached to strobe and camera.
It gets hooked and tangled on everything, not as bad as a reel and line but still frustrating.

Conditions were not great with 5m vis green cruddy water and heaps of dive classes in the vicinity.

Saturday, 12 February 2011

Fibre optic sync cord from audio cable

Fibre optic sync cords are a great option for underwater strobes but they are expensive and delicate. A 0.5m coiled sync cord costs around A$70. Digital audio cable, which is basically the same thing, costs maybe A$2.00 a meter.

Here's how I adapted a 10m toslink audio cable ($20 on ebay) to work with my Inon strobes. I'm intending to use the long sync cord to setup some remote strobe lighting in sites like wrecks, under ledges and behind pier piles.

First to make the slave strobe end I cut through one of the Toslink plugs leaving a lip which would sit inside an Inon sensor cover.

I carefully shaped the lip diameter and depth to hold the cable in the sensor cover and allow the sensor cover to be screwed over the sensor.

To make sure the cable didn't pull out of the lip I used plumber's PVC pipe glue.

That seemed to work very well but I also used heat shrink tube and cable ties to secure it even more.

The sensor cover can still rotate freely.

Finally to fit the master strobe end of the sync cord.
I cut the plug off leaving a raw end and made a PVC bracket to hold it in front of the master strobe.

The bracket fits around the sensor and the PVC material is thin enough, about 1mm, to allow the sensor cover to screw down securely, holding the bracket in place.

Here's the whole setup, now all I need is some decent vis!

Sunday, 6 February 2011

Inon strobe on Gorillapod

Here's how I mounted the strobe onto the tripod.

A piece of aluminium flat was shaped to fit the gorillapod mount with a cutout slot to accommodate the locking lug.

The strobe and gorillapod combination is negatively buoyant but I added a 0.3kg ankle weight for a bit more stability.

Off-camera underwater strobe

I have started mucking around with a remotely triggered strobe underwater.

The aim of this is to create more interesting lighting. Using an off camera strobe to add rim lighting or even back lighting can add depth and drama to an image.

The tricky bit is actually getting the remote flash to fire. Water absorbs light much more than air so the in-built Inon slave sensor is only effective over about 1.5m. Any further back and the main strobe will not trigger the remote strobe, at least in our murky sub-temperate water. 
There are a couple of solutions.
1. Use a really long sync cord, either fibre optic or electrical.
2. Use a more sensitive electronic remote sensor. These are available for Ikelite strobes but not my Inons, although one should be available very soon. 

I have ordered 10m of fibre optic audio cable to try a long sync cord. One end will sit in front of my main strobe and the other will connect to the remote strobe. This means the cable will be visible in the shot of course.

Stay tuned for new developments.