Hi I need advice for choosing an appropriate halogen fiber optic illuminator for microscopy. With self supporting light guide (so it stays in position without me needing to hold it)
What wattage should I choose?
Are there any quality models of compact size (not too bulky)?
Post subject: Re: Choosing a fiberoptic illuminator
Posted: Wed Feb 08, 2012 4:11 am
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Joined: Fri May 12, 2006 11:24 am Posts: 7523 Location: Rome, Italy
cascaillou wrote:
What wattage should I choose?
100 W is the minimum suggested, 150 W is a good choice
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Are there any quality models of compact size (not too bulky)?
what do you mean with "bulky"? usually fiber optic illuminators are compact in sizes.
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What brands would you suggest?
i'd go for used stuffs on ebay, definitely worth a try, Fostec, Dolan jenner. Those are my fav but there are others..... If you're in EU be careful the illuminator could run even under 220 vac.....
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Any other recommandations?
ther are plenty on ebay, so try to bid on a recent model, it wouldn't be so difficult to find one in mint conditions for 100 $ orso...
This would be a good one to buy. Make him a $100 offer and he will take it I am sure. He ships worldwide. I have bought a couple of gadgets from him over the years.
This illluminator is a DCR III DCR stands for DC regulated. This means the light output is very steady which is good if you you should ever upgrade to a scanning camera or three shot camera. there is no downside. This unit also has a mechanical iris diaphragm in addition to the voltage/current control dimmer. this allows dimming without changing color temperature. Finally the FOSTEC DCR II and III but not the I have international power supplies and can be used anywhere in the world.
If you are searching ebay add Volpi to the list and their german alter egos Scholly and NCL which you may be more likely to find in Europe. For some reason European sellers open with too high prices.
Post subject: Re: Choosing a fiberoptic illuminator
Posted: Wed Feb 08, 2012 5:54 pm
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Joined: Tue Jan 02, 2007 8:20 pm Posts: 2659
If you look at the last photograph in the auction you will see it operates on 90-265volts AC 50/60 Hz This means it will operate anywhere in the world. You do have to set a switch that tells it 115 or 230 range.
It looks real clean to me and I think this is a very good seller. I think I have bought from them more than once. (no connection to them otherwise etc etc)
Here is a dark field illuminator. Offer them about $150 for it. It will plug right into your DCRIII and it is small and will fit under almost any scope because its not very tall. It comes with a stop to block direct light from the annular ring from pointing upwards. It has a 1/4"-20 thread female socket like the bottom of a camera. See finewater gems photo's or private message him about how well it works. I have traded stuff with this seller and found him quite reasonable.
Post subject: Re: Choosing a fiberoptic illuminator
Posted: Wed Feb 08, 2012 6:24 pm
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Joined: Sun Jun 28, 2009 9:56 am Posts: 1284
ouch the lightguide is more expensive than the lightsource!
no way to use this light guide in a conventional way (meaning without the dakrfield ring)? Is it a 'self supporting' light guid (so I don't need to hold it)?
Post subject: Re: Choosing a fiberoptic illuminator
Posted: Wed Feb 08, 2012 6:44 pm
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Joined: Tue Jan 02, 2007 8:20 pm Posts: 2659
I think the FOSTEC price is about double the ebay asking price. But the seller will deal unless they are marching out the door at that price which I doubt.
The fiber optic cable is a limp cable. This is good because the ones that are supposed to be "obedient" never are. you set them then they move. Its better to use limp ones and have a method of holding them in place. Go over to photomacrography.net and look at the threads on friction arms.
This light guide cannot really be used on the barrel of the scope (ie shining downwards onto the specimen while mounted on the scope objective) because the bottom plate does not come off.
But if you search ebay with the term "fiber optic ringlight" zillions of them will come up (well several any way) and a small minority of them will be actual auctions where the seller opens for $2.00 and sells to the highest bidder. Sometimes you can steal all kinds of different light guides from auction like these.
Post subject: Re: Choosing a fiberoptic illuminator
Posted: Thu Feb 09, 2012 11:02 am
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Joined: Sun Jun 28, 2009 9:56 am Posts: 1284
If I got you right, this device is a fiberoptic powered darkfield, however the darkfield ring can't be separated from the fiberoptic cable, meaning that I cannot use the cable for pinpoint illumination, right?
btw, my scope can't focus on the surface of any sample exceeding 2cm in height (because the scope head cannot rise high enough), which means that such darkfield is probably not really suitable for the scope I presently own as that would reduce even more the sample size I can focus on (which is already little).
ps: thank you for your haggling advice: got the lightsource at 100, just as you had said
Last edited by cascaillou on Thu Feb 09, 2012 11:46 am, edited 2 times in total.
Post subject: Re: Choosing a fiberoptic illuminator
Posted: Thu Feb 09, 2012 11:17 am
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Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Quote:
The fiber optic cable is a limp cable. This is good because the ones that are supposed to be "obedient" never are. you set them then they move. Its better to use limp ones and have a method of holding them in place. Go over to photomacrography.net and look at the threads on friction arms.
Totally disagree on this one Gene. I find the limp cables useless for me, and the stiff ones perfect for my needs. The stiff yet flexible fiber optic cables are extremely obedient in my lab.
Post subject: Re: Choosing a fiberoptic illuminator
Posted: Thu Feb 09, 2012 3:04 pm
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Joined: Tue Jan 02, 2007 8:20 pm Posts: 2659
This is a situation where one piece of advice does not fit all.
I would not even have given it until very recently when I have had some experience with obedient goosenecks that were disobedient. A couple of them have been at work where one was oem ed to a large local microscope distributor. It was made by Techniquip. They used to sell to GIA and many others. I suspect that the one that I ran across was recent enough to come from the far east.
I think it also may depend on who made the gooseneck and how old it is. Even disobedient ones can probably be "beaten into submission". I certainly have used some that stayed where you put them. Going back to the days when the Dolan Jenner units were the only ones around. They pretty much invented the business and made the units that GIA resold for about the first twenty years. Then GIA switched to TechniQuip. TechniQuip still sells a 250 watt and its a lot cheaper than the corresponding Schott. Also like FOSTEC is much easier to fit to various light guides.
I also have some pretty fancy FOSTEC obedients that I don't like very well. These have fancy lenses affixed to them. But they are so frustrating to use that I always make other arrangements. (I like ringlights better anyway) It is likely that they need to be forced into their permanent operating position often enough for them to stay that way.
The pictures below show the method that is the preferred method used by the Z stackers over at PM.net With those holders you loosen a knob, point it where you want it and when you tighten the knob it stays put with no drifting. (pictures courtesy another Wild Zombie Army Field Marshall)
It may well be overkill for gemological uses. It requires more bench space and is more expensive. But it is optically and mechanically superior to wound metal or plastic goosenecks. It allows the use of larger diameter fiber bundles so more light can be piped, and also allows more exact placement without argument from the gooseneck. And the holders shown are now available from China for much lower prices. They used to be much more expensive (Made by Fisso and Foba of Germany and Switzerland and Noga of Israel. They are now available no name for a fraction of the price. Similar units can be gotten at Harbor Freight) It is true that the limp fiber guides are of almost no use unless you have a method to hold them exactly where you want them.
If anybody wants to try these here are some references:
Post subject: Re: Choosing a fiberoptic illuminator
Posted: Thu Feb 09, 2012 5:35 pm
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Joined: Sun Jun 28, 2009 9:56 am Posts: 1284
G4lab, if I got you right, the ringlight device you initially pointed to me (on ebay) is a fiberoptic powered darkfield, however the darkfield ring can't be separated from the fiberoptic cable, meaning that I cannot use the cable for pinpoint illumination, is that right?
also, my scope can't focus on the surface of any sample exceeding 2cm in height (because the scope head cannot rise high enough), which means that such darkfield is probably not really suitable for the scope I presently own as that would reduce even more the sample size I can focus on (which is already little), unless I can manage to replace my current scope darkfield by this ring light (meaning incorporating the ring light into the microscope base instead of placing it on top of it)
Yeah this one cannot fit pointing downwards because it has a bottom plate that covers the whole aluminum piece. It is about one and a half inches tall ie 35 to maybe 50mm.
It would not be suitable for your scope. Most ringlights probably would not be. I think the only suitable guides for your scope would be the standard single or double gooseneck or if you want to buy a little fancier for the future , some limp ones with a holder.
http://www.ebay.com/itm/ANNULAR-RING-LI ... _500wt_725 Here is one with a hole through it to be mounted facing down on a scope (although you could make a great dark field with it too) I show it to illustrate the hole which is not present on that first one. It is blocked by a mounting plate.
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