XPG optic question or two

[East Tn Bowman]

The project i'm working on is possibly planning the use of the xpg r5s or something probably going about 750 ma, the reflector that was with the original version isn't going to work for the xpgs, and i'm wanting to find some new ones here's what i have

 

[gcbryan]

This is the closest that I know of (for this price you might be able to make it work)... http://www.dealextreme.com/details.dx/sku.32954

 

[TorchBoy]

It would be cool to see what you can come up with if you make something yourself.

 

[yellow]

the reflector that was with the original version isn't going to work for the xpgs,

why should it not work?
Did You try?

... I am doing some project I planned for years:
getting cheapo light: http://www.dealextreme.com/details.dx/sku.3607
and mod it with all the old (and upcoming) led I have...
... to be able to show the evolution of led, differences, ...
all with the same light(s) and the different led, which are run with about the same current.

There is only a minor difference between XP-G and the original mounted XR-E led.
With XR-E, the light is a little bit more focused (way less than I expected from all those "larger emitting surface leading to wider hotspot"-typing) and has a pronounced edge between hotspot and spill.
XP-G on the other hand offers visibly brighter spill, much more fade hotspot/spill, tiny bit wider hotspot (like 1-2 deg), hotspot seemingly less bright.

 

[East Tn Bowman]

why should it not work?
Did You try?

... I am doing some project I planned for years:
getting cheapo light: http://www.dealextreme.com/details.dx/sku.3607
and mod it with all the old (and upcoming) led I have...
... to be able to show the evolution of led, differences, ...
all with the same light(s) and the different led, which are run with about the same current.

There is only a minor difference between XP-G and the original mounted XR-E led.
With XR-E, the light is a little bit more focused (way less than I expected from all those "larger emitting surface leading to wider hotspot"-typing) and has a pronounced edge between hotspot and spill.
XP-G on the other hand offers visibly brighter spill, much more fade hotspot/spill, tiny bit wider hotspot (like 1-2 deg), hotspot seemingly less bright.

It was too wide of a spot instead, the hot spot was about 3 times the size of the one that was using the original diode

 

[TorchBoy]

Getting a really tight focus with an XP-G is difficult, and all else being equal require larger reflectors/optics that other popular LEDs do to get the same size spot. CPFer ma_sha1 found they do quite well with a 66 mm aspheric lens.

 

[East Tn Bowman]

Getting a really tight focus with an XP-G is difficult, and all else being equal require larger reflectors/optics that other popular LEDs do to get the same size spot. CPFer ma_sha1 found they do quite well with a 66 mm aspheric lens.

wonder if i can find a magnifying glass that has a 1inch lense in it cheap that i can hack appart ? hmm, if that works then i may be onto something if i can get the focal distance right?.... hmmm and we can change the battery sourcing as well, might be looking towards something rechargable since these things when used are used and used and used, and the batteries get old to buy

 

[TorchBoy]

A magnifying glass has way too long a focal length for most LED uses, hence why people use short focal length aspheric lenses. How about a 26 mm lens? http://www.dealextreme.com/details.dx/sku.13900 - being acrylic you could trim it down. Packhorse (makes dive lights here on CPF) gives the 21 mm version a positive review. http://www.dealextreme.com/details.dx/sku.13903

 

[East Tn Bowman]

A magnifying glass has way too long a focal length for most LED uses, hence why people use short focal length aspheric lenses. How about a 26 mm lens? http://www.dealextreme.com/details.dx/sku.13900 - being acrylic you could trim it down. Packhorse (makes dive lights here on CPF) gives the 21 mm version a positive review. http://www.dealextreme.com/details.dx/sku.13903

i think that 26 mm lens will work as is i have about 29mm inside the hood on it, whats the best way to hold these bad guys down? some sort of ring or custom spacer required?

 

[TorchBoy]

I suggested those two because I thought you had 1 inch to work with, but if you have that much room you could add the 28 mm glass lens http://www.dealextreme.com/details.dx/sku.5297 to your consideration list. It's not great quality, but it does work. A quick test just now indicates its best intensity is a little short of perfect focus, maybe because it can catch more light being closer to the LED. I've used hot melt glue to hold one of these lenses in place in a very quickly modded headlamp, but a ring bracket thing would be preferable. The lens has a little rim around its edge.

 

[East Tn Bowman]

So the 28mm lens has a metal ring around the glass? I've really enjoyed the Led stuff this far, any good threads that will help me figure out a power source that i could put in the tube, CR123 or the 3 AAA battery size, or would i have to find a new main tube for the light, i should have more parts from this guy tomorrow, its really pretty cool setup, attaches to a bow, has a pressure momentary switch that is mounted so you don't have to have a third hand, but its only pushing about 100 lumens from the white led, even if the lumens aren't a whole lot more if i can figure out how to get the focal point right on the xpg it will out perform the reflector and xr setup since its a nice circle but not really bright

 

[TorchBoy]

So the 28mm lens has a metal ring around the glass?

It comes with a flat bit (of glass, no metal) around the lens part.

Can't think of any CPF threads for battery holders. If I wanted something rugged I'd probably buy a cheap 3x AAA torch from DX (there's one that glows in the dark!) and remove the LEDs from it, running a lead to the Cree head.