Getting a tight beam with xm-l's in divelights

dexter9

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Joined
Dec 19, 2011
Messages
27
Since the majority of the users here use Cree XM-L's i thought it would be nice if we could share some information/experiences about the solutions we have when we want to get a tight beam out of this led.
I use this simple web calculator to calculate the angle of the beam:
http://www.csgnetwork.com/righttricalc.html


The best lens that i could find on the internet for this is this one, but i didn't got to test it, they say 3.7° :
http://www.led-tech.de/en/High-Powe...L,-XP-G,-XB-D,-OSLON...--LT-1813_106_122.html
3.7 it's like the scubapro nova 230, whitch is really tight

I have a lense that lens makes a 18° beam so it's no point in pointing to it since it can't be considered tight.
I know that other people from here used the Ahorton aspheric, the 44mm DX aspheric, fresnel lenses.
What results can be expected?
 

Packhorse

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Joined
Nov 29, 2007
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1,912
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New Zealand
First. If you want to get the widest range of opinions then post it http://www.candlepowerforums.com/vb/forumdisplay.php?17-Homemade-and-Modified-Flashlights-Discussion forum instead. Its not really a dive related only subject.

Second. For a tighter beam you generally want to use a larger optic. The issue here is that the XML is "only" a 1000 lumen LED. If you want lots of light then you need a few of them. Which means lots of optics. This soon leads to a very large light head if you want lots of light and a tight beam. You need to compromise some where.

The optic you linked to gives 3.7degree half beam... or 7.4 degree full beam. Tight, but not super tight.

Interestingly it gives the Osram Oslon 150 a 1.7degree half beam. Thats pretty tight. Never heard of this LED before. They do a Oslon 80 too which may be better suited to an aspheric lens
 

jspeybro

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Aug 13, 2009
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Belgium
Interestingly it gives the Osram Oslon 150 a 1.7degree half beam. Thats pretty tight. Never heard of this LED before. They do a Oslon 80 too which may be better suited to an aspheric lens

I heard of this led at work and has an interesting 80° angle instead of the more common 110° so really interesting for aspherics I would say. The once we use at work are about the same as cree XPG, so in combination with an aspheric, the oslon is probably a better solution.
 

DIWdiver

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Jan 27, 2010
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2,725
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Connecticut, USA
Just did some research on the Osram web site. The 80degree LEDs are all limited to 1A max drive current. And it doesn't look like they have anything that can put out anywhere near 1000 lm of white light. The one 3A LED I saw claimed 59 lm/W.
 

H20doctor

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Joined
Jan 16, 2008
Messages
222
Location
seattle
the best reflector i use for XML and SST 50 / 90 is this one [h=1]53mm*30mm Aluminum Textured/OP Reflector for Cree XR-E Emitters sku #18841[/h]
it has a really nice spot and lots of throw... good luck with your build
 
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