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gobiodon

DIY fiber optics ringflash and CFWA adapters

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I’ve recently finished two DIY projects using fiber optic cables to redirect the light from an external strobe around the port. It was an old idea mainly inspired by Joris van den Heuvel over at fuzzcraft.com but other inspirations also came from the wetpixel (Alex’s home made ring flash and the fibresnoot by Phil). I don’t have two small strobes but one and I’ve found Alex’s solution a bit bulky, so I went on the fiber optic route.

My add on to the previous DIY project was that I had used the hook side of Velcro tape to space the fibers.

 

After putting some glue on it I’ve covered with the “loop” side and pressed overnight under heavy books. I’ve used heat shrink tubes to hold together the strands. These branches have been sewn at the Velcro part to an oblong rubber band providing a support for the whole set-up. (see picture below).

5062852380_db6b6b6283.jpg

Next thing was to connect the fibers to the strobe. I’ve drilled wholes into a plastic piece (found in the kitchen but in the first version I used a Lego block) and pushed through the fiber bundles and glued them tight. Actually it was quite complicated because I haven’t left enough overhangs for the branches. When the glue has dried and hardened completely I cut and polished the fibers. The whole adapter was fixed on the port by Velcro (sewn on the rubber band) and by a buckle (good Velcro alone is probably fine).

5063135648_0ef782dc5d.jpg

See the “werkphotos” here:

http://www.flickr.com/photos/fiberstrobe/s...57624999795069/

 

I’ve tested recently the adapter in Croatia in the Adriatic sea. I had limited time and I did only 6 dives. The whole rig worked quite well with my sigma 50mm macro (see some pictures below):

5063877701_3d2f1a9d1d.jpg

 

5064490066_8bd68a1925.jpg

 

More pictures you can see here:

http://www.flickr.com/photos/fiberstrobe/s...ith/5064490066/

 

http://www.flickr.com/photos/fiberstrobe/s...57625125010858/

 

I’ve also tested with a 100mm macro but due to the long port to subject distance, the strobe power was just not enough. At f11 and iso200 the pictures were only correctly exposed at the closest distance with bright subjects. In addition I haven’t seen much advantage over using a simple strobe placed above or right above the port. The big advantage of the adapter was that after realizing that the power through the fiber optics is not enough I just simply repositioned my strobe and used as a standard external strobe.

 

In the next post I will discuss the "halfring adapter" developed for CFWA photography.

 

Marcell

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After completing the first version of the ringflash adapter, it came to my mind that the same concept could be used also for close focus wide angle photography. Finally the strobe to subject distance can be very short in this case. I really liked the versatility of the Velcro, therefore I decided to use it to fix the fiber optics branches to the port shade. I glued the loop part to the shade and the hook part to the fiber branches. I sacrificed a diffuser of the strobe to attach the branches to the strobe. The inner part of the diffuser was covered by aluminium foil and the external side was painted black:

5062531543_a3ca79a80f.jpg

Here you can see the final set-up. I decided to create only a half-ring and omitted branches from the under part of the port shade. In this way I can avoid potential overexposure from sandy bottom :

5062535365_9f9e9ee0a5.jpg

A picture taken in the mirror:

5062530529_7820f33647.jpg

And some pictures with the rig (sigma 15mm fisheye on apc-c sony a100):

5064537676_360af71c8c.jpg

 

5064539046_787e68d970.jpg

 

5064539506_26c27aa1e4.jpg

 

More picture here:

 

http://www.flickr.com/photos/fiberstrobe/s...57625125058252/

 

Cheers

 

Marcell

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Nice one Marcell!

Those first 2 images are great.

I like the concept that this could be used for both macro and CFWA work.

I'll look forward to more pics when you get the chance to play.

Cheers,

Phil

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Nice one Marcell!

Those first 2 images are great.

I like the concept that this could be used for both macro and CFWA work.

I'll look forward to more pics when you get the chance to play.

Cheers,

Phil

 

Thanks, Phil!

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This is a great idea Marcell and I love your images. I'm keen to do something similar and would like to make some sort of removable ring that I could use on either a mini-dome for CFWA or a flat port for macro. Both ports have the same circumference.

I'll be using 2 x DS50s and thought I might use one for coverage of the top half of the port and the other for the lower half. That way the lower one could be turned off for 'over sand' shots that you mentioned.

So, a couple of questions.

Firstly, are you using TTL and does it work well with this arrangement?

Secondly, the circumference of my ports is around 30cm. How many strands in total would you suggest for optimum coverage?

Thanks,

John

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This is a great idea Marcell and I love your images. I'm keen to do something similar and would like to make some sort of removable ring that I could use on either a mini-dome for CFWA or a flat port for macro. Both ports have the same circumference.

I'll be using 2 x DS50s and thought I might use one for coverage of the top half of the port and the other for the lower half. That way the lower one could be turned off for 'over sand' shots that you mentioned.

So, a couple of questions.

Firstly, are you using TTL and does it work well with this arrangement?

Secondly, the circumference of my ports is around 30cm. How many strands in total would you suggest for optimum coverage?

Thanks,

John

 

Hi John,

 

I think it's possible to build something for two strobes and you can arrange the strands that the first strobe would illuminate only the top half. I wanted to try the ringflash with a second strobe to use the ring as a fill flash and the second as a key light. But you can also turn it off.

 

It works perfectly well with TTL. I haven't made any optimisation on strand number but as I remember I used 144 0.75mm strand but I would use a bit more per strobe.

On the other hand, using too many strands would make the whole adapter less flexible.

Good luck for building the adapter and don't forget to post some pictures.

 

Marcell

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Very interesting.

I'm new to underwater photography, so excuse me if this is a dumb question, but what is the advantage to fiber optics over regular strobes or some form of consistent LED lighting?

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With a slightly different skew, I came across this rather tidy acrylic solution. Not saying it is suitable for UW use but the concept is certainly transportable.

 

http://www.ray-flash.com/

 

@ Ron, the ring flash concept allows an even, diffuse light close to the port/lens for short focus macro. Often the positioning of strobes is inhibited by the housing and may be prone to uneven areas of lighting.

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Thanks Balrog. I should have been more clear. I've been shooting for four decades and understand the ring flash concept. My question concerns the quality and output of fiber optics in comparison to other sources. I'm also wondering if there is a difference in WB settings?

Someone mentioned "diffused." Is fiber optic lighting an inherently more diffused than other light sources?

Gobiodon: Your invention seems to work well for concentrating light for true macro, but appears to confined for close-up or UWA shots. I wonder if there would be a way to adjust the angle of aim or deflect light outward for more even for wider coverage as well: possibly a inflatable bladder under the end of the optical fibers that could be pumped up like a blood-pressure cup to alter the angle of illumination?

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With a slightly different skew, I came across this rather tidy acrylic solution. Not saying it is suitable for UW use but the concept is certainly transportable.

 

http://www.ray-flash.com/

 

A similar cheap underwater product would be fine IMHO

 

Marcell

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Thanks Balrog. I should have been more clear. I've been shooting for four decades and understand the ring flash concept. My question concerns the quality and output of fiber optics in comparison to other sources. I'm also wondering if there is a difference in WB settings?

Someone mentioned "diffused." Is fiber optic lighting an inherently more diffused than other light sources?

Gobiodon: Your invention seems to work well for concentrating light for true macro, but appears to confined for close-up or UWA shots. I wonder if there would be a way to adjust the angle of aim or deflect light outward for more even for wider coverage as well: possibly a inflatable bladder under the end of the optical fibers that could be pumped up like a blood-pressure cup to alter the angle of illumination?

 

Hallo Ron,

 

You don't need special WB adjustment (it doesn't alter the color) and works perfectly with TTL. It's not really more diffused light, but if the subject in the centre, the light is coming from every direction, so the effect is similar to diffused light. Actually the light leaves the fibers in a sharp angle.

I also feel the limitation of the CFWA version and I was also thinking some way to change the aim of the fibers. No I have two layers. In the first layer tha fibers are bent a bit into the center, while in the second layer the fibers are looking straight forward. In the wide angle version maybe it would be possible to change this by simply changing the attachment to the shade. In that way one layer would be positioned straight, while the other would look slightly outwards.

But you idea is also good and I can imagine other mechanical solutions to change the angle of the illumination. However, the whole concept works only for close subjects and will never illuminate a real wide underwater scene.

 

Marcell

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