the emitter with the highest surface brightness

[Nos]

Hi guys, im about to build my ultimate mag aspheric, but i dont know which emitter is the best for it. basicly there are three emitters :shrug:


Cree xr-e R2 with 242 lumens at 1A, here driven @1400ma (max from spec is 1000ma)
Cree xr-c P3 with 80 lumens at 0,5A here driven @700ma (max 500ma)
Luxeon K2 220 with 300 lumens at 1,5A here driven @1800ma (max 1500ma)

what will give the best results? :huh:

 

[LukeA]

One you may want to consider is the XP-E. It has as many lumens as the XR-E, but projects them from a smaller apparent area.

This comparison isn't as easy as it sounds. You have to take into consideration the better beam patterns of the XR-E and XR-C against the high lumen level of the K2 and the relatively small apparent die size of the XP-E.

 

[Nos]

hmmmmm i didnt even consider a xp-e into because i allready had the chance to compare it to a xr-e side by side, both r2.
the projection of the xpe is only a hint smaller, unsharp and not brighter than the xr-e.
and till the xp-e is 700ma max rated i cant push it any further

:candle: any other experiences? :thinking:

 

[LukeA]

hmmmmm i didnt even consider a xp-e into because i allready had the chance to compare it to a xr-e both emmiters R2 bin side by side.
the xp-e projection of the xpe is only a hint smaller, und sharp and not brighter than the xr-e.
and till the xp-e is 700ma max rated i cant push it any further

:candle: any other experiences? :thinking:

So a smaller apparent die removes the XP-E from consideration? And the only one of those LEDs you can't overdrive is the XP-E? What do you think the rated drive currents are for the XR-E and XR-C? How about the K2?

 

[mash.m]

this days i testet the new k2 with 300l max @ 1500ma, but it is not so bright then a cree q5 at 1000ma. i can´t belive this so i send back the emitter to the supplier. they check the led and everything seems to be ok.
i have ordered a new k2 300l max led from an other supplier to compare.maybe the first one is a fake.
tomorrow i make some pictures that will show the k2 and the cree with a aspherical lens.

markus

 

[Nos]

hmmm. maybe that was a bit unclear.

i have 2 aspheric mags lieing here, one uses an XR-E the other one a XP-E.
the smaller apparent die of the XP-E produces a 2cm smaller die at the wall than the XR-E mag @ 2,5m.
Brightness is the same :ironic:




but the main reason why i wont take a XP-E is because it isnt any better than a xr-e at 1A.
And since the max current of a XP-E is only 700ma, 1A is driving it really hard.
equal to a XR-E @1,4A (allmost exactly the same factor)

and a XR-E @1,4A beats the XP-E @1A for sure

the XR-C with its tiny die will be far more interesting...but i doubt that it can take 1A (its 500ma max) ill correct that to 700ma and add the max current from the specs.

I guess the battle will be K2 or XR-E ....... but i have no idea which will do better in a aspheric setup

 

[Nos]

Hi Markus, sorry to hear about the poor performance of the (maybe fake) K2.

Lets hope the next one will do better, im looking forward to your pictures

 

[SemiMan]

I would go with the XRE versus XP-E or K2. The XRE has a much narrower emission angle. A lot more light will hit the lens.

Nos, when you compared the brightness, was that by eye-perception or actually measured?

Semiman

 

[HarryN]

this days i testet the new k2 with 300l max @ 1500ma, but it is not so bright then a cree q5 at 1000ma. i can´t belive this so i send back the emitter to the supplier. they check the led and everything seems to be ok.
i have ordered a new k2 300l max led from an other supplier to compare.maybe the first one is a fake.
tomorrow i make some pictures that will show the k2 and the cree with a aspherical lens.

markus

I am just curious - how in the world did you properly install a K2, including soldering it in and proper heat sinking if you could then send it back to the supplier ?

Please don't tell us that you used some arctic silver grease without a mechanical hold down and this is the basis for the comparison. :sick2:

Make sure you are getting the TFFC version.

Moving on, the K2 has a lambertian shaped output (more or less - emits every direction). If you are going to depend on the lens, then the only light reaching it is what comes from the front. Light from the sides is more or less lost.

An aspherical lens will perform best with an LED package that has practically all of the light come directly from the front (narrow beam pattern) even if the total light is less.

 

[Nos]

I would go with the XRE versus XP-E or K2. The XRE has a much narrower emission angle. A lot more light will hit the lens.

Nos, when you compared the brightness, was that by eye-perception or actually measured?

Semiman

I have no lux meter at moment :shrug: but comparing those two side by side with the bare eye, is not exact but should be ok :sigh:

 

[mash.m]

hi,

the led is mountet on a star. under the star some paste and then two screws on a copper block. so removing is no problem remoing and send back!

so here now the pictures to compare. left mc-e at 1000ma/die right k2 tffc 300lm 1500ma:

left mc-e warmwhite 1400ma/die, middle k2 tffc 300lm max@ 1500ma and right k2 tffc 300lm max@ 1500ma:

so i think the first k2 is wrong or a fake. i will contact the supplier with this facts.

here a picture at 2000ma k2 vs k2:

markus

 

[Nos]

hey nice pics Markus :thumbsup:
the K2 knocks the MC-E out for sure (was obvious) do you have a XR-E @1,4 that you can compare directly to the K2 @2A?

btw, do you know the colour bin of the cold white MC-E, it looks pretty cold compared to the K2

 

[HarryN]

Hi Marcus - thanks for the information and pictures. 2,000 ma into the K2 - wow.

The (good) K2 TFFC stars you have are certainly brighter than what Future is selling, especially in the star format. Interestingly, the emitters they have for sale are pretty good.

Where did you get them if you don't mind my asking ?

It almost appears that the "not as good" K2 TFFC is getting more dim with increased current - or is that an optical illusion ?

 

[mash.m]

you are right - "K2 TFFC is getting more dim with increased current"

at this moment i will not offer the name of the supplier, cause i wan to wait for the answer. but it is the most popular led dealer here in germany!

the good one is from www.dotlight.de

markus

 

[mash.m]

so here now the compare q5 vs. k2

upper both @ 700ma
middle both @ 1500ma
lower both @ 2500ma

the q5 can handle this high power with good heatsink. others here at cpf also use the cree at this high power. i think for 1000 hours it is ok. the k2 have the more beautyfull die.

hope this picture help you with your choice.

markus

 

[Nos]

thaks a lot, that review really helped me a lot

 

[mash.m]

cheers

 

[AlexGT]

Do you have a guess at how many lumens are you getting at 2 amps with the K2?

 

[mash.m]

don´t know, but i think 350lm are real

 

[Tatjanamagic]

Hmm I think that emitter with highest surface brightness is R2, Q5 is almost same but R2 is better...


However I would be happy if U find better emitter for aspherical lenses.

In fact please add your consideration and any news about led emitters here.

Thanks.