B & L fiber optic/ flash setup

Eric F · Post by **Eric F** » Tue Mar 31, 2009 6:10 pm

This small and old fiber optic unit, designed for the illuminators used with Bausch & Lomb stereoscopes in the 1960's (? - anyways, many years ago) has good potential for use with flash systems on cameras and bellows. The small size (guides are 30cm long) and light weight makes them suitable for cameras in the field (see http://www.pbase.com/pganzel/image/91003812 and other images on Pete Ganzel's site). As I mentioned a few days ago on the 'Technical and Studio Photography -- Macro and Close-up forum' these are currently available at the Surplus Shed for $50 (http://www.surplusshed.com/pages/item/t1531.html) [NOTE: I emailed the 'Shed yesterday and they verified that some units were still available]. I have adapted one of these for use with a Canon MT-24EX Macro Twin Lite and include some photos of this setup.

This shows most of the B&L unit (minus the 1-1/2" ring that attaches the 4-legged 'spider' to the stereo microscope, which does not seem to have an application for camera use today). Also included are a 70mm lens hood with 4 small bolts (used to hold the 'spider' legs after they are cut-off) and the top half of a plastic bottle ("Purell" sanitizer) that fits over one of the Twin Lites, which transmits the 'flash' to the guides - attached with the help of the little cap (part of the B&L unit). The inside of the cap and the bottle are painted white; foam is added to the plastic bottle part, to help it fit tightly on the Twin Lite; and the outside of the bottle is painted black -- to reduce stray flash. The large black piece is a velcro 'jacket' that attaches the light guides to the Twin Lite. Note the B&L notes that show how unit was originally used.

Plastic bottle attached to light guides with velcro jacket (which will be turned 90 degrees and strapped over the Twin Lite).

Items in place on stand holding Canon EOS 40D with OM tele auto tube and Zuiko 20mm f:2 macro lens. Lens hood (attached to a T-mount unit at end of auto tube) holds 4 cut-off spider legs with light guides inserted. Plastic caps with ping-pong diffusers are at ends of guide tubes. One Twin Lite head with light guide attached is hidden behind XYZ table.

I am still practicing with this setup but early results seem promising. Recent shots with Zuiko 20mm pushed to near extreme (extended to +230mm, yielding about 15X) also pushed flash to limits (full power, 1/1). Light was just sufficient at f4 but not at f5.6, however diffusers were in place (which reduced light a lot).

AndrewC · Post by **AndrewC** » Wed Apr 01, 2009 2:45 am

Nice setup - I've got one of these in the bottom of my box of fibre optics but alas I paid a bit more than the current price from Surplus Shed

Neat trick with the bottle top - you might want to try lining it with aluminium foil to increase the light making it to the end of the bundle. Or better still see if you can find a more tapered bottle so that it will funnel the light better ? I've been playing with some adapters using StoFen type diffusers to clip onto my Nikon flashes and then trying to mould a light funnel up to the bundle collector.

Andrew

JGVilla · Post by **JGVilla** » Wed Apr 01, 2009 8:18 am

Eric,

Thank you very much for showing your setup using the B&L Fiber Optic guides.

I think I can definitely use one of these in my lighting setup,
so I ordered one from the Surplus Shed as they still have several units available.

Hope I'm not running in somebody else's tracks?

lauriek · Post by **lauriek** » Wed Apr 01, 2009 8:26 am

Looks handy!

I ordered one as well!

Eric F · Post by **Eric F** » Wed Apr 01, 2009 9:16 am

Andrew - thanks for the good suggestions. I will try to add foil. I've been looking for more tapered bottles but the ones I've found mainly have odd, asymmetrical shapes - bent to be hand-held. Will keep trying...

JG, Laurie - hope these light guides work well for you.

lauriek · Post by **lauriek** » Wed Apr 01, 2009 9:18 am

I'm wondering if a semi-silvered mirror in front of the flash would increase output by catching and redirecting light bouncing off/around the bottle top, or if it would decrease it by reducing the initial flash output?

Eric F · Post by **Eric F** » Wed Apr 01, 2009 9:40 am

Well, I have thought that a collimator lens of some sort would probably be the best bet. It would collect, then concentrate the broad flash into a narrow beam aimed at the tip of the guide bundle. I just don't know enough about lenses to configure one at present.

lauriek · Post by **lauriek** » Wed Apr 01, 2009 10:53 am

A reversed fresnel lens maybe?

Planapo · Post by **Planapo** » Wed Apr 01, 2009 11:13 am

Thanks from me too, for posting your set-up using these light guides, Eric!

To my fellow Europeans, or extra-Americans

: Can anybody tell me what they charge for shipping these fibre guides across the pond?

--Betty

AndrewC · Post by **AndrewC** » Wed Apr 01, 2009 11:23 am

lauriek wrote:I'm wondering if a semi-silvered mirror in front of the flash would increase output by catching and redirecting light bouncing off/around the bottle top, or if it would decrease it by reducing the initial flash output?

Probably decrease it significantly. The back of the flash head is a reflector and that will take care of any light bouncing back into the flash itself. It wouldn't hurt to have some reflective material around the window. alu foil works pretty effectively or if you want to up the ante you could use some stick on mirror tiles or plastic mirror or if you want to get really serious you could try some front silvered optical glass but you are very far down the road of diminishing returns by then !

You can also do interesting things with clear epoxy, solid acrylic light funnels and lots of time to waste

By the way, the easy way to do this is with a Lumiquest Snoot, add some extra reflective material on the inside and then just wedge your fibre optic in the end

http://www.lumiquest.com/lq891.htm

Andrew

JGVilla · Post by **JGVilla** » Wed Apr 01, 2009 2:56 pm

Planapo wrote:Can anybody tell me what they charge for shipping these fibre guides across the pond?

I got the following quote from them:
Shipping via USPS First Class International Air Mail is 11.95 and via USPS Priority Mail is $29.75.
I choose 1st class international air mail. Never had any problems with that.

Also I requested them to state on the package:
"Second hand equipment, surplus items"

Over here anything less than € 50.00 will pass customs without a glitch (famous last words

)

Eric F · Post by **Eric F** » Wed Apr 01, 2009 5:40 pm

Laurie, I'm not sure about a fresnel lens (reversed or not). I was thinking of something like a simple biconvex lens - but this is just a guess on my part.

Andrew, that Lumiquest Snoot looks like a good idea; definitely something to check out.

ChrisR · Post by **ChrisR** » Sat Apr 11, 2009 10:10 am

I'm trying to order one as well.
I have some old enlarger condenser lenses which would be about the right size to focus the image of the gun head onto the fiber end. You need to collect the light, not shade it. I fear the white insides of the snoot wouldn't gain you very much.

g4lab · Post by **g4lab** » Sat Apr 11, 2009 12:33 pm

What is needed is a negative cylindrical lens to change (reduce) the aspect ratio of the flash tube and make it from a line into almost a point, or at least a shorter line.

A tapering tube internally lined with aluminum foil should help too.

One could also fabricate a long gradually tapered snoot from from acrylic with a taper such that light could not escape because of total internal reflection. The negative cylindrical lens could be incorporated into the entry side. The internal reflection would have the same effect as foil on the inside of a snoot You would want the taper to be about 30 degrees so that you would not be right at the critical angle of 42 degrees.

Here is a wikipedia explanation that happens to use acrylic as the example

If one wanted to use a dedicated flash below are links to some current auctions from a reliable surplus seller. Both units are intended to be used with fiber optics.

Here

and here

Eric F · Post by **Eric F** » Sun Apr 12, 2009 9:10 am

Interesting info g4lab. It is nice to get a preferred angle for total internal reflection; I will try to setup a system with a 30 degree taper. I have tried to line my plastic bottle top with aluminum foil: complete failure! I think a better solution would be bright, shiny paint -- like fake chrome paint used for plastic model cars. As for a condenser lens, wouldn't an "aspherical condenser lens" be better than a cylindrical lens? It seems to me a cylindrical lens would give off a narrow slit of light, instead of a concentrated point like with an aspherical lens (flat on one side -- toward flash source, convex on the other -- toward fiber bundle).