Are there any long throw high CRI lights at all?

Check out the Nightwatch NS22 Seeker on Neal’s Gadgets. 27 euro, reflector is very good and C8 size, available in SST20 4000/3000K 95CRI, and even with dome (I bought the 3000K version) I found it remarkably throwy.

Don’t neutral white and cool white emitters tend to be more efficient than warm white hi CRI emitters?

Warm tints have a useful impact to the eye mostly for near field illumination. Long range, not so much. And with NW or CW producing more light… isn’t that the high priority, for longer range illumination?

That’s always been my understanding.

Warmer tints scatter less light than cool tints. If you’re looking right down the beam, that’s an issue.

It’s a balance. Less lumens with less scatter is good for throwers, up to a point.

Also, I think for the OP’s use (hunting), he wants high CRI for better color separation.

My understanding is that warm light is more appealing at low intensity, and cool for high intensity.

The problem with these high intensity low CRI lights is they aren’t useful for much besides seeing the outline. The color is just so wrong, and your brain takes longer to distinguish say, a young coon from a barn cat. A puddle of runoff from horse piss/poo was almost totally yellow with a tinge of brown to the XHP HI, while the SST20 was yellow+deep reddish brown like the puddle was in the morning daylight. Even up fairly close the coon’s color was washed out, and tinged blue. Low CRI blue lights are absolutely way worse than low cri warm lights, even though I prefer neutral/slightly cool.

Low CRI lights are horrible with red and brown usually. Even greens are off with the ODL20C.

Personally I prefer ~5000k but the only thing for that is the Optisolis nobody is using.

Completely agree. CRI 70 vs 90 is not easy to detect visually if R9 is the same. However, a high R9 vs low R9 is very easy to detect and makes a world of a difference. To me, negative DUV and high R9 makes the biggest difference in light quality.

OK, why would someone need to dedome an SST-20?

I mean, the SST-20 by itself throws 30% more per lumen compared to the XP-L HI, so a 95CRI version will not have any deficit in throw.

I didn’t know it, thanks!
I see that there’s CRI90 from 2700K all the way to 7000K. :slight_smile:
The challenge is to find a nice tint though….and then - there are still no great drivers easily available.

Any source for that? I’ve read that SST-20 is throwier. But I don’t remember seeing such huge difference.
And then - SST-20 maxes out at about half the lumens.

Emisar D4S specs are one published source. My own testing with SST-20 vs XP-L HI has shown that the SST-20 has more cd/lm, to the point where there’s no loss of throw with a regulated driver going from a low-CRI XP-L HI to a high-CRI SST-20. With a FET driver, the SST-20 has more throw because it has lower forward voltage and therefore draws more current.

Thanks for the input.

The way efficiency is defined is, in my honest opinion, wrong. Lumens are defined around a presumed luminosity function and is very subjective. If efficiency were defined by radiant flux or (for example) non-weighed 400 to 700nm emission the difference would likely be negligible.

I've built warm white throwers and couldn't care less about others opinion in this respect. They're a lot stealthier in the night, by the way.

Your honest opinion assumes that humans are a spectrometer, and you are completely ignoring biology.
If we use a flashlight, the usefulness is completely dependent on which wavelengths we see and which we do not see. It is a very good idea to include that in the efficiency definition, if you fail to do that, efficiency numbers would be meaningless as far as light sources for illumination are concerned (radiation sources for detection by machines is a completely different subject and not relevant in a flashlight forum). You can value the wavelengths that we do not see as much as you like, you will still not see them. That is what the luminosity function tells us. The luminosity function is not presumed, it is measured, and it varies only in details among the human population.

So the way that efficiency is defined may be wrong in your opinion, in reality it is right.

I tried to collect data on SST-20 throw.
I got the following:

DOMED:

Nightwatch NS22 Seeker SST-20 72 cd/lm
Nightwatch NS22 Seeker SST-40 31 cd/lm
.08585 cd/mm²/lm.

https://skylumen.com/products/emisar-d4vn-smallest-18650-quad
Emisar D4 SST-20 7.1 cd/lm
Emisar D4 XP-L HI 7.2 cd/lm (average of 2)
–1% difference, .08871 cd/mm²/lm.

https://skylumen.com/products/eagletac-d25cvn-the-micro-searchlight-r-1
Eagletac D25C SST-20 21.7 cd/lm
Eagletac D25C White 2 35.6 cd/lm
.09760 cd/mm²/lm.

https://skylumen.com/products/emisar-d4vn-smallest-18650-quad
Emisar D4 SST-20 7.1 cd/lm
Emisar D4 White Flat 21.6 cd/lm
.09922 cd/mm²/lm.

Convoy L2 SST-20 178 cd/lm
Convoy L2 XP-L HI 160 cd/lm
+11.7% difference, .10015 cd/mm²/lm.

https://intl-outdoor.com/emisar-d4s-26650-high-power-led-flashlight-p-932.html?zenid=c34625b9c0483c7ad0db13932650843f
Emisar D4S SST-20 13.74 cd/lm (average for 3 different variants)
Emisar D4S XP-L HI 10.47 cd/lm
+31.3% difference, .11773 cd/mm²/lm.

https://skylumen.com/products/eagletac-d25cvn-the-micro-searchlight-r-1
Eagletac D25C SST-20 21.7 cd/lm
Eagletac D25C White Flat 54.8 cd/lm
.11860 cd/mm²/lm.

SHAVED:

E2L triple shaved SST-20 8.1 cd/lm
E2L triple XP-L HI 6.6 cd/lm
+23% quite low for shaved…
.11029 cd/mm²/lm.

GT Mini shaved SST-20 256 cd/lm
GT Mini Black Flat 462 cd/lm
.14580 cd/mm²/lm.

Convoy S2+ shaved SST-20 25 cd/lm
Convoy S2+ XP-L HI 25 cd/lm
+78.4% difference, .15996 cd/mm²/lm.

GT Mini shaved SST-20 256 cd/lm
GT Mini XP-L HI 131 cd/lm
+95.4% difference. Note that this includes focus tuning that SST-20 likely received but XP-L HI didn’t.
.1752 cd/mm²/lm.

Does anyone know of other direct measurements? Stock vs dedomed SST-20 would be useful as well…

Anyway - for those capable enough to do it, dedomed clearly looks like the way to go. Especially that dedoming was shown to reduce SST-20 greenness.

The reduced green-ness probably only counts for the 95CRI SST-20 leds.

It would be useful to have the comparisons with the same current but you will have to do of course with what data is available.

OK, I’m out of data. In my previous post you can see the estimated surface luminosity of SST-20, both domed and dedomed, based on comparison with known emitters.
I could do also a direct comparison with XP-L HD but I lack sufrace luminosity data for it. I could estimate that…but it would be cumbersome and imprecise.

So…there’s a lot of noise in the data. I don’t know what is the reason. The best result is 38% higher than the worst…and neither is a lone outlier.

The average surface luminosity seems to be about 0.1 cd/mm²/lm, 10% better than XP-L HI.
Dedoming ups that by about 50% but causes quite big output drop.

Note that the results are very rough, with this kind of differences we’d need many more data points to draw accurate conclusions.

Biology studies how humans work in a very materialistic and inaccurate way. Like medical disciplines, they don't even know a @#$% of what the mind is. Is this any different from what I'm saying here? But they can at least measure properly, don't they? No demeaning talk, all right. Let me, for example, quote the following from the Lumen (unit) wiki article:

Sorry but the eye is not more or less efficient, it just transmit signals. The efficiency thing is mentally defined and those parameters can or could be accessed and changed via the subconscious or even the unconscious mind. So much for science.

The luminosity function was measured (when?). We evolve and change as our mind patterns or beliefs do. It should be updated then, doesn't it? But horror! If we do that, then we can no longer compare old versus new lumens and such. Yes, it could happen with a conversion algorithm. Suffice to say I do no longer care much with regards to lumen output, it is a “rigged” thing. Actual full spectrum measurement data is a lot better, it is objective. Guess what? Do I dislike the efficiency thing as defined? YES. People needs to understand that, the way luminous efficiency is defined low colour accuracy/low CRI emitters will always look or be more efficient against accurate colour rendering/high CRI ones. And I will go even further: What is one of the reasons behind the led emitter green-ness scourge and high DUV? Lumen efficiency, of course.

Conclusion: the industry is mainly creating efficient emitters which look “white enough”. This is the price you are paying for this efficiency thing to impress the @#$% and the numbers to look big… and crap.
For those of you who like efficiency, aim for some crap CRI leds and enjoy.
In the meantime, change your minds great advice is.

Signed,

A efficiency lover.

Cheers :-)

P.S.: serve me a round of incandescence, please. ;-)

This false assumption of efficiency must be why the makers all omit red, afaik it’s the least sensitive color to the eyes.
Rubbish…

@Barkuti

You better not become a biologist!

A pretty widespread mistake that you also show is that subjects are more important if you can measure them more accurately. Or the other way around: anything that you can not measure accurately is not worth measuring at all.

In reality such relation does not exist: many things that can be measured very accurately are utterly unimportant, while many more things let themselves measure very poorly but are extremely important.

In the last case, dismissing existing information on the basis of a superficial presumption of subjectivity or inaccuracy (which is what you do) is a capital error. Data must always be used keeping the amount of accuracy in mind, but simply ignoring it is a total waste of effort and valuable data.

Many biologal problems are eminently difficult to investigate, there’s not many yes or no answers, and many answers show a relative low accuracy compared to say many physics problems. This has nothing to do with biologists (you seem to value them lower than other scientists) but with the difficult subject that biology is. Yet the answers that biologists give do contain an immense amount of important information, to the amount that currently more than 60% of all scientific research is of biological nature, for good reason.

The luminosity function was first measured about a hundred years ago, with some minor corrections in the seventies. You may want to read into what timescale evolution takes place.

The efficiency debate is an interesting one, because it seems like there’s so many different components involved that are also subject to variation by context. Thus, it’s hard to pin down precisely.

  1. Lumens are how much light is given off
  2. Lux is how bright your surface will be
  3. Candela measures the visible intensity from the light source.

Then the perception of the human eye for the light being produced.

“Interestingly - when a user compares two identical flashlight using identical reflectors - one with Cool White LED, and one with Neutral White - our BRAIN says the yellowish NEUTRAL is MUCH dimmer than the bluish COOL… but look again, most users can actually see a lot better and clearer with the NEUTRAL light.”

As for efficiency… “COOL LED are still leading in lumens output over NEUTRAL LED, but not by much anymore.
With today’s high output LED - NEUTRAL tint can now be as close as 6-7% of the lumens output of similar Cool White LED, and human eyes typically can’t see less than 30% difference in lumens output.”

So ultimately, better to have a more neutral or slightly warmer tint… which will be easier on the eyes.