DIY Ring Flash with a 150-Element Optical Fiber Whip

| 13 Comments |
Lixtal: 48Svær: Debatlitteratur og populærvidenskabelige artikler
  • aNyhed
  • Digg it!
  • Add to Technorati
  • Stumble It!
  • Google Bookmarks
  • Facebook
  • Facebook
There are plenty of do-it-yourself ring flash projects around, either sporting any number of white LEDs, or foil-clad tube constructions directing the light from a flash to a ring around the lens. However, state of the art LEDs still produce rather little light, and there's a flexible and perhaps even more efficient alternative to transporting light via a tube fitted with reflective walls: optical fibers.

UFO Fiber Optics LampOptical fibers are specifically made to transport light, so my idea was to construct a ring light based on the same principle as the popular optical fiber lamp: a large number of optical fibers are collected at the light source, leaving the other ends fanning out in a spherical shape. For flash purposes, this light source is of course a regular flash unit, and the other ends of the fiber optics cables are fitted in the circular outline of the ring flash, that is, where other DIY people have placed LEDs. Unlike LED constructions, however, this construction allows the camera to adjust its flash intensity automatically, and it doesn't require a power supply. Also, with a large number of fibers, the light should be very evenly distributed, possibly eliminating the need for a diffuser.

It turned out it was difficult to find suppliers of fiber optical cables in my country. The only supplier I found agreed to cut 150 pieces of fibers (length about 50 cm, ø 1,0 mm each) for me and melt together all the fibers in one end. Fiber Optics WhipMy reliance on the supplier probably makes my particular solution rather costly compared to what may be expected in other countries. However, it's not necessary to melt the ends together (it simply allows the fibers to absorb more light, yielding a better output), so cutting and bundling the fibers is something anyone can do without professional help. The optical fibers themselves don't seem to be expensive at all.

I tested the light conducting capability of the fiber optics whip by holding the glued end in front of my camera's built-in flash unit and looking at the free ends while firing the flash. Don't do this at home: it worked much better than I had hoped, and was practically the same as looking straight into a flash at close range.

Drilling holes for the fiber-optic ring flashThe next part was to construct the ring where the optical fiber ends are attached. I cut the ring from a piece of acrylic glass (you may of course also use wood, cardboard, plastic, or metal) with 150 ø 1,2 mm holes drilled in a uniform pattern. The holes are organized in concentric circles with 36, 37, 38, and 39 holes and slightly rotated to distribute the fiber cable ends as evenly as possible. I used Inkscape to draw a template for the ring. You may download the template here. I created four templates (one for each circle) instead of plotting all holes into a single template, because otherwise the paper would probably crumble before I was even halfway through drilling. I also waited to saw the inner circle and the outline in the acrylic glass until I had drilled all the holes. The uneven edges of the cut were easily smoothed by sanding the plastic.

Ring flash with the first few fiber optic cables glued in placeNext, I inserted all the fiber optic cable ends in the holes and fastened them with superglue. I did this in several rounds to allow the superglue to dry before working on the next bundle of cables. I also fitted the acrylic glass ring with a ring of cardboard so that could it slide snugly onto the lens.

For the other end of the fiber optics cable whip, I created a fixture for the camera's built-in flash by cutting and gluing a small fixture of cardboard that could slide onto the flash in one end and onto the fiber optics whip in the other end, and covered it with aluminum foil inside.

With all fibers and the inner cardboard ring attached (including an unexpected 151st fiber that also happened to be too short and was left dangling) the ring conducts light from a regular desk lamp just nicely:

Light through Fiber Optics WhipI used cable strips to bundle the fiber cables together in order to ease its fitting onto the lens. In the end, "The Ram" hardly hardly improves the looks of the camera, but that was kind of an expected trade-off:

Nikon D70 with Fiber Optics Ring Flash
In practice, the ring and the fibers block some of the measuring light and probably cause a slight miscalculation of the target flash intensity. However, the resulting light is reasonably well dispersed as illustrated by this snapshot of a nearby cactus flower:

Ring Flash Example
There's probably room for some improvement in the link between the whip and the flash, but all in all I think this experiment illustrates that fiber optic cables can be successfully applied as a ring flash.

13 Comments

This is awesome, specially because you where going the same route as I tried to go.
In my country it's very difficult to finde optic fiber as well (for ilumination, not data transfer). But I managed to find someone who had some and they actually gave me some for free.

The thing is, it was cut with scissors and I didn't have the glued end.
After trying unsuccessfully to make it work I decided the problem was that all the strands were actually BROKEN on their ends (cut with scissors actually broke them, not so much as smoothly cut them, since they're a type of glass) and so the angles at the end of each strand where jagged and facing different ways.

Thus, the light transmitted from the flash was weak and very diffused :(

Do you know of any way I could be able to glue and smooth those ends and cut the fiber getting an even smooth cut for the lose ends of the strands (away from the flash).

Or maybe the people you worked this with could ship it?

Anyway, right now I have about a couple of meters of optic fiber that I can't use and I ended up looking for other solutions for my macro lighting

You can find my email at my website www.oscarblanco.net

I would appreciate any suggestions, advice or feedback.

Great job on your experiment!

Hi!

Found you through petapixel and a friend told me that the photo of your camera has been featured on Reddit.

Thought you might want to know that =)

Very cool idea and I'd love to see a portrait with the ring flash, I'd love to see the effect of 150 fibres in a ring in the eyes of a person.

I'm curious if they look like small dots or if they show up as one big ring of light.

Again, love the build!

Thanks for your feedback. You're right! Sanding must be the answer!
I'm thinking I can use silicon glue and just dip the ends into it, then rap them up in tape, let them dry, and then sand :)
I think the heat gun might not be the answer, because you could end up with deformed, twisted and engrossed ends, maybe even blackened. Plastic doesn't love heat :D

How many wires did you use to create this ?

I thought so. Why did you choose 1mm wire - in your opinion is this approach better than i.e. 2mm ?

Hey there would you mind letting me know which hosting company you're using? I've loaded your blog in 3 different web browsers and I must say this blog loads a lot quicker then most. Can you suggest a good hosting provider at a reasonable price? Kudos, I appreciate it!

Leave a comment

Ældre indlæg

Sider

Om dette indlæg

Denne side indeholder et enkelt indlæg af Ole Wolf, udgivet d. 02.03.2011 19:11.

Forrige indlæg: Tegneseriehelt

Næste indlæg:Majestætsfornærmelser

Find de nyeste indlæg på forsiden, eller søg i de ældre indlæg to find all content.