Trustfire TR-J1 review

[Jak Crow]

The Sola 1200 has a 500 lumen spot, so it certainly isn't any more than that.

So more than 200.

 

[jmneill]

A bit OT, but just a few quick questions:

1. For the Surefire lights, were the lumens from the SF lights measured independently, or are they based on SF website data?
2. What emitters do SF lights use? There's a particular one - M6LT which SF rates at 900lm - that I'm personally interested in.

I'm asking because I have very limited exposure with SF lights and wanted to get the perspective of someone with experience.

Thanks.

1) I have never looked into this. I just have to believe that with the hundreds of millions of dollars of Surfire products (not just lights, but even a 23 million dollar suppressor contract) being sold to Government, military, SWAT, fire rescue agencies etc that these guys are going to be pretty forthright when it comes to the specs on their products. None of these dive light manufacturers are being held to any type of governmental standards that I am aware of.

2) Since I believe the Surefire M6LT uses the same emitter that TrustFire is claiming to use, the flux U2(and personally experiencing the difference in visual light output) I can only assume that there is something fishy here. (remember, this is China were talking about) I wouldn't argue if I hadn't personally seen output of numerous Surefire lights of different lumens.


FWIW, and if #2 wasn't a trick question and you are indeed interested in the M6LT, I can guarantee you wont be dissapointed.

EDIT: On second look I see TrustFire is claiming to be using the T6? This doesn't seem to stack up right to the output I see wth the TrustFire. Could it be that they are using the T6, but not marrynig it up to optimal battery for it's potential? (SF123A's are 3V 1400mAh, but almost always used in a series of two or more)

 

[Ed Palma]

I would imagine that when tested side by side, assuming the M6LT uses the XML as well, it would have more throw than the TR-J1 and thus may be perceived by the human eye as being brighter (greater lux). This may be attributable to the geometry of the reflector which focuses more of the light onto one spot. If the heads are removed however, I believe the difference in total lumens would be more or less the same. The difference between the terms "lumens" and "lux" have been the subject of many numerous threads and is beyond the scope of discussion of the TR-J1.

1) 2) Since I believe the Surefire M6LT uses the same emitter that TrustFire is claiming to use, the flux U2(and personally experiencing the difference in visual light output) I can only assume that there is something fishy here. (remember, this is China were talking about) I wouldn't argue if I hadn't personally seen output of numerous Surefire lights of different lumens.

The spec sheet that I posted wherein I derived the numbers were directly from the Cree website, which is a company based in Durham, North Carolina, the company that manufactures the emitters. Being one of the major players in the production of emitters (along with SSC, Luminus, Osram, Philips, etc) I think they have to be pretty forthright when it comes to their spec sheet. I have yet to come across 3rd party data based on actual testing that contradicts the data - which I admittedly started looking for only after the spec sheet was questioned.

---------- Post added May 18th, 2012 at 07:23 AM ----------

EDIT: On second look I see TrustFire is claiming to be using the T6? This doesn't seem to stack up right to the output I see wth the TrustFire. Could it be that they are using the T6, but not marrynig it up to optimal battery for it's potential? (SF123A's are 3V 1400mAh, but almost always used in a series of two or more)

Aside from light head geometry, there might be some driver differences which could account for the differences as well. I'll have to take tail-cap measurements of the current draw and post them later.

 

[sucnip]

Do any of you have a multi-meter? Measure the tailcap current draw at each of the settings. Tailcap current less driver efficiency will give you the best approximation of light output. My guess is the T6 LED is driven at around 2A which should equate to around 600-800 Lumen. Keep in mind that this is when you first turn it on with a fresh battery. Within 30 seconds the light output will sag due to thermal properties and how well the LED is heat sinked.

 

[Jak Crow]

All the lights I mentioned above also appear more powerful than a Princeton Tec Miniwave LED which is rated for 337 lumens.

 

[Ed Palma]

Interesting...

I took some tail-cap readings. Tested the light at high, medium, and low. Battery was a Smallsun 18650, "2400mah" at 3.97v. Seems the driver is only putting out half what an XML is capable of:

High setting: 1.79A

Medium (50%): 0.83A

Low (10%): 0.17A

Interpolating the data with the Cree specs for an XML, the "emitter" lumens would be around:

High - prob ~ 600lm
Medium - prob ~300 lm
Low - less than 100 lm

Throw in your reflector losses so you can get the "OTF" lumens. Still, pretty bright. I was wondering how they could claim an 80 minute run-time on high. I guess it's because the light isn't driven that hard.

When I get my other light, I'll have an n=2 so it'll be better data.

 

[Jak Crow]

I can live with a 500-600lm light for 40 bucks.

 

[Ed Palma]

I can live with a 500-600lm light for 40 bucks.

Likewise

Tailcap current less driver efficiency will give you the best approximation of light output.

Sucnip, I forgot to ask both here and on CPF: How can I approximate the driver efficiency?

 

[jmneill]

I guess I will post one more time since I am now more perplexed than ever. I in now way want to contradict the math above since I do not understand it to begin with. That said if the math is correct and the TrustFire is really a 600 lumen light, why is the M910A (rated @ 200 lumens if I remember correctly) I have mounted on an an M4 appear to be brighter, if indeed it has a third the output? Doc, you have done alot more homework on this than I, but it doesnt make sense if you forget the math, turn out the lights and look at the light.

EDIT: I wasn't going to include this in the post, but changed my mind in the interest of the thread. It's been a couple years since I got rid of it, but I had a SF 600 lumen tactical light that I got rid of due to unacceptable battery life. I had it mounted on AK underfolder and used to play with in the yard at night. The thing lit up the yard at night like a police search light. (slight exag) Friends couldn't believe it. I take this TF light out in the same yard and there is no comparison. None, zero, zilch, nada.

 

[Ed Palma]

I will admit to being a newbie flashaholic (so if a more experienced flashaholic can jump in, please do so). That said - based on what I've read - technically speaking a lumen should be a lumen, ie it is the total light output from a source. In practice though, people make distinctions between "emitter" lumens and "out-the-front (OTF)" lumens. Due to losses from the reflector, there is usually a drop from comparing the emitter to the OTF lumens. Thus, since cree is an emitter manufacturer, their measurements are from the emitter, and SF being a light manufacturer, they measure OTF.

Another possible source of confusion is that people tend to focus on the hot spot, disregarding the spill. As stated earlier, lumens are the total output, and not just the intensity of the perceived light at a single point. One post on CPF that illustrates this point:

Last time I checked, the human eye does not have the ability to integrate the output of a light source. If it had this ability, then one would not need an integrating sphere to measure output. The eye perceives intensity (or brightness - measured in lux) which is an entirely different thing altogether from output (measured in lumens)...

Take a very floody light, like a Zebralight and shine it at the wall from a distance of say, 20ft. Take another light with a similar output, but one which has a distinct hotspot, and shine it at the wall from same distance. Ask a person which one is brighter. Unless the person is a lighting engineer, most will tell you that the light with hotspot is brighter. Do this outside on a dark night and the result will be even more dramatic.

Another factor to take into consideration is the way SF rates their lights. They are known to be very conservative in their ratings, so I have a feeling that if you took on of their 200lm lights like the M910A into an integrating sphere, it would probably rate much higher than that. Now, while most people do not have integrating spheres, they have come up with various methods to objectively quantify light output rather than base it on perception. Here's a screenshot of results by TurboBB on CPF showing the difference in Surefire lights published lumen ratings and 3rd party measurements which highlight how much SF under-rates their lights:

..

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* values with (*) are manufacturer ratings

Like I said, I have very limited exposure to surefire lights. Thus I'd like to ask if you could take comparative beamshots between the SF lights and the TR-J1 so we can see for ourselves the differences that you note.

For the calculations above, since I don't have a light meter (let alone an integrating sphere), I have to rely on the manufacturer's published data for their light, hence my utilization of the Cree spec sheet.