Against all advice, am going to have a go at building my own fiber optic illuminator. I have a big, honking Alien Bees AB1600 flash on order--am very tired of using speedlights, with their long recharge time, low power, and battery-eating ways. I know the venerable Vivitar 283 has an available A/C adapter, but the recharge time is listed at 11 seconds. Aack! My most recent stack contained 921 frames. . . .
As long as I'm doing this, I'd the unit to accept any fiber optic bundle I find to throw at it. And that seems to require an adjustable chuck. Some medical FO units have a version of a Jacobs chuck, and I could cannibalize one, but the ones I've found barely accept over 1/2-inch light guides. Surely there is something out there with much more range.
So far, the best thing I come up with is a 3-jaw chuck that machinists use. They appear to come in many sizes, and some could accomodate nearly any conceivable FO bundle. On the downside, they are expensive and very heavy--massively overbuilt for my purposes.
Any better ideas?
Thanks! Cheers,
--Chris
Adjustable chuck for fiber optic illuminator
Moderators: rjlittlefield, ChrisR, Chris S., Pau
Re: Adjustable chuck for fiber optic illuminator
Just as a benchmark, when I am using an SB-23 flash for direct illumination, throttled way down to about 1/10,000" the READY light does not even blink when it fires. Batteries last for weeks (at least a couple of thousand frames).Chris S. wrote:Against all advice, am going to have a go at building my own fiber optic illuminator. I have a big, honking Alien Bees AB1600 flash on order--am very tired of using speedlights, with their long recharge time, low power, and battery-eating ways. I know the venerable Vivitar 283 has an available A/C adapter, but the recharge time is listed at 11 seconds. Aack! My most recent stack contained 921 frames. . . .
..
What's the flash time on the Bee ? Their website says 1/300" at 1/32 power and it gets longer as you throttle back.
You should be able to get some sort of large diameter fresnel lens to focus it to a point and then a smaller lens to collimate into a FO ?
For a chuck , the idea you threw out before about opposing V's would probably grip anything but I'd probably make it as V^V to give a bit more support.
rgds, Andrew
"Is that an accurate dictionary ? Charlie Eppes
"Is that an accurate dictionary ? Charlie Eppes
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ChrisLilley
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Re: Adjustable chuck for fiber optic illuminator
... at full power. Once you get down to 1/4, 1/16 power then the recharge time is much faster. At least, it is with my Vivitar 285HV flashes, I assume that this holds true of the 283 as well.Chris S. wrote: I know the venerable Vivitar 283 has an available A/C adapter, but the recharge time is listed at 11 seconds.
The last stack I did with flash was set to photograph every 2 seconds; and that is mostly mechanical settling time (my D90 does not have mirror-up) rather than being limited by flash recharge.
The fiber optic cables used for medical purposes (surgeons headlights
fiber optic lit retractors, and the zillions of types of endoscopes that they have now) all fit within the usual half inch size adjustable chuck that these have.
I have a couple of them and they all have this limitation and none of them will accept a Schott FOStec nor a Volpi ferrule which is the type of guides I prefer. They are too small.
You need to find one designed to be used on a lathe so that it has a through hole. Just going to the hardware store or industrial supply and buying a Jacobs chuck might not yield one with such a hole. But if you can find one that is fenestrated like that then anything above 5/8 or 3/4 should do the trick. Metal would be preferred since you will probably be using a hot light in addition to the flash.
fiber optic lit retractors, and the zillions of types of endoscopes that they have now) all fit within the usual half inch size adjustable chuck that these have.
I have a couple of them and they all have this limitation and none of them will accept a Schott FOStec nor a Volpi ferrule which is the type of guides I prefer. They are too small.
You need to find one designed to be used on a lathe so that it has a through hole. Just going to the hardware store or industrial supply and buying a Jacobs chuck might not yield one with such a hole. But if you can find one that is fenestrated like that then anything above 5/8 or 3/4 should do the trick. Metal would be preferred since you will probably be using a hot light in addition to the flash.
Andrew and Chris, I’ve been using Nikon SB26 and SB800 speedlights. I suspect they are in a roughly similar league with the Vivitar 283.
These speedlights are fine in some situations, but not all. The other day, for example, I was shooting a 60x objective with 200mm total extension and ping pong ball diffusion. The subject was black carbon collected as airborne particulates—something of a light sponge (especially when compared with the substrate of glass fibers, which are very reflective and refractive if not lit with care). Two SB26 units at point blank range on full power managed the task, but barely. I want to cross polarize, and that will eat up a big percentage of my light. Add in the inefficiencies inherent in herding light into optical fiber, and it seems like a good idea to start with as much light as I can get.
Andrew, you likely read the Bee’s flash duration here: http://www.alienbees.com/specs.html . That’s all I have to go on as well. I would note, though, that the range of 1/300-1/600 second is the “t.1” flash duration—so it includes the faint “tails” at the beginning and end of the flash duration, down to when the tube is emitting just ten percent of the peak output. I’m not sure how much those tails contribute to overall exposure. The “t.5” flash duration range is 1/900-1/1800 second. Which set of numbers is the better guide to real-life photography? I don’t know—but even the slowest of these numbers is fast enough for me.
You and I are thinking along the same lines with the Fresnel lens—my first thought is to try one intended for an overhead projector (they’re widely available for about $25 plus shipping). That should concentrate the light--not sure yet what I'll try for collimation, though a second Fresnel lens seems like a candidate. (Also, from what some folks have reported, I'm not entirely sure I will need to collimate the light--will experiment.)
This is bearing in mind that others report better success in simply placing the optical fibers right up against the light source. While I understand that such an approach is more efficient, the capability to just plug in any FO cable seems like an advantage worth sacrificing for.
I do think three opposing V’s could do a nice job of gripping any bundle. But when I started thinking about making one myself, I looked to see if something purpose-built already existed. I found the “3 jaw chuck” used on machinists’ lathes, which looks better for this purpose than a Jacob’s chuck. There are some nice demonstrations of these chucks on Youtube, and many are available on eBay. On the downside, they are overbuilt for optical purposes—heavier and larger than I really need. But at something like $50 for a used one, maybe a better bet than making a chuck myself?
Thanks, Gene—as you point out, I did mean a 3-jaw chuck of the type used on lathes, and not the Jacob’s type. Thanks for checking your collection of Jacob’s chucks to see if any were fenestrated. And it’s useful to know that a ¾ inch “bore” should handle any bundle I’m likely to come across. Though I might go with an inch just to be sure. . . .
These speedlights are fine in some situations, but not all. The other day, for example, I was shooting a 60x objective with 200mm total extension and ping pong ball diffusion. The subject was black carbon collected as airborne particulates—something of a light sponge (especially when compared with the substrate of glass fibers, which are very reflective and refractive if not lit with care). Two SB26 units at point blank range on full power managed the task, but barely. I want to cross polarize, and that will eat up a big percentage of my light. Add in the inefficiencies inherent in herding light into optical fiber, and it seems like a good idea to start with as much light as I can get.
Andrew, you likely read the Bee’s flash duration here: http://www.alienbees.com/specs.html . That’s all I have to go on as well. I would note, though, that the range of 1/300-1/600 second is the “t.1” flash duration—so it includes the faint “tails” at the beginning and end of the flash duration, down to when the tube is emitting just ten percent of the peak output. I’m not sure how much those tails contribute to overall exposure. The “t.5” flash duration range is 1/900-1/1800 second. Which set of numbers is the better guide to real-life photography? I don’t know—but even the slowest of these numbers is fast enough for me.
You and I are thinking along the same lines with the Fresnel lens—my first thought is to try one intended for an overhead projector (they’re widely available for about $25 plus shipping). That should concentrate the light--not sure yet what I'll try for collimation, though a second Fresnel lens seems like a candidate. (Also, from what some folks have reported, I'm not entirely sure I will need to collimate the light--will experiment.)
This is bearing in mind that others report better success in simply placing the optical fibers right up against the light source. While I understand that such an approach is more efficient, the capability to just plug in any FO cable seems like an advantage worth sacrificing for.
I do think three opposing V’s could do a nice job of gripping any bundle. But when I started thinking about making one myself, I looked to see if something purpose-built already existed. I found the “3 jaw chuck” used on machinists’ lathes, which looks better for this purpose than a Jacob’s chuck. There are some nice demonstrations of these chucks on Youtube, and many are available on eBay. On the downside, they are overbuilt for optical purposes—heavier and larger than I really need. But at something like $50 for a used one, maybe a better bet than making a chuck myself?
Thanks, Gene—as you point out, I did mean a 3-jaw chuck of the type used on lathes, and not the Jacob’s type. Thanks for checking your collection of Jacob’s chucks to see if any were fenestrated. And it’s useful to know that a ¾ inch “bore” should handle any bundle I’m likely to come across. Though I might go with an inch just to be sure. . . .
Three quarters is definitely starting to be big enough. Depending on how the light infeed is done even a bigger bundle could go in. You could bore that out a certain amount since it would only need to be as thick as sheet metal to do this job.
But I have been a student of fiber optic bundles for quite a while and I think this would do ya. JMO
You could bore it out completely and mount it to the front or top wall of the box using screws going into the back of it. Have to take it apart and check the details first. though.
http://www.mini-lathe.com/Mini_lathe/Re ... x3/5x3.htm
But I have been a student of fiber optic bundles for quite a while and I think this would do ya. JMO
You could bore it out completely and mount it to the front or top wall of the box using screws going into the back of it. Have to take it apart and check the details first. though.
http://www.mini-lathe.com/Mini_lathe/Re ... x3/5x3.htm
I suspect a Jacobs style chuck would be better suited. Most of them have a through hole and mount on solid adapters. Here's the cheap page from Enco: http://www.use-enco.com/CGI/INLMK32?PARTPG=INSRAR2
p.s. Wouldn't standard electrical connectors work just as well as a big old chuck?
p.s. Wouldn't standard electrical connectors work just as well as a big old chuck?
Elf, that page links me to counter-sinking bits. Did check the Enco Web site, though. It appears to me that only their biggest and most expensive Jacobs chuck would hold bigger FO bundles, and the price makes me go "oof." Am definitely hoping to source something used on eBay, unless I home brew something.
What do you mean by "standard electrical connectors"? Can't think of what electrical parts you are referring to.
What do you mean by "standard electrical connectors"? Can't think of what electrical parts you are referring to.
That's odd, it goes to the cheap Jacob chuck page on my computerChris S. wrote:Elf, that page links me to counter-sinking bits. Did check the Enco Web site, though. It appears to me that only their biggest and most expensive Jacobs chuck would hold bigger FO bundles, and the price makes me go "oof." Am definitely hoping to source something used on eBay, unless I home brew something.
What do you mean by "standard electrical connectors"? Can't think of what electrical parts you are referring to.
Graingers carries a lot of interesting items as well. This was what I was thinking would work:
http://www.grainger.com/Grainger/flexib ... ch&sst=All
but there may be other items that would work better.
(edit) Like this: http://www.grainger.com/Grainger/wwg/se ... sst=subset
or this: http://www.grainger.com/Grainger/wwg/se ... sst=subset
Hey, Elf, I think maybe you've found the mother lode.
I really like the item at your last link--much like a Jacobs chuck for cable. And they have three versions that, collectively, would cover FO bundle diameters from 1/8" to 3/4". At under $8 each, the whole set wouldn't be too expensive, and would be very easy to mount. On the downside, the item is made of nylon--not sure how that would stand up to the heat from my modeling light, or if I substitute in a continuous light source. That said, I don't want to heat up the optical fibers, either--so the point may be moot.
Now that you've got me looking at Grainger "cord connectors" for strain relief, I see a wide variety of them--some constructed out of metal.
Thanks for pointing me in this direction. May be the way to go. Thanks!
I really like the item at your last link--much like a Jacobs chuck for cable. And they have three versions that, collectively, would cover FO bundle diameters from 1/8" to 3/4". At under $8 each, the whole set wouldn't be too expensive, and would be very easy to mount. On the downside, the item is made of nylon--not sure how that would stand up to the heat from my modeling light, or if I substitute in a continuous light source. That said, I don't want to heat up the optical fibers, either--so the point may be moot.
Now that you've got me looking at Grainger "cord connectors" for strain relief, I see a wide variety of them--some constructed out of metal.
Thanks for pointing me in this direction. May be the way to go. Thanks!
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ChrisLilley
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- Location: Nice, France (I'm British)
g4lab, I just purchased one of these--thanks for your suggestion. It's not the cheapest solution, but I like the idea that with a simple turn of the ring, any FO bundle is instantly and securely clamped. Some of the other approaches do also look attractive, but a talk with my fabricator Don Wilson tipped the balance for me back toward this chuck. Anyway, so ordered..
Cheers,
--Chris