“A part of what makes it so small is the fact that it uses a multi-led optics, isn’t it?”
No. A single led catadioptric could have been smaller. Hell, you could simply make a mule.
Multi-led optics are shorter because their height is related to diameter of the lenses.
Please accept and understand that there is no way in hell a multi-led setup beats a single led at throw on an equal fight.
Multiple people here are trying to explain this fairly simple concept to you.
We’re talking about good throw to size (with size defined as volume, not diameter). djozz has shown that D4vn with XP-G2 is not a leader here, but I still maintain that it is quite good.
If Emisar made it a mule it would be smaller, but clearly would be bested by many non-18650 lights.
With catadioptric? If there was a suitable one on the market, it would be marginally shorter. Scaling down 10158 to 24 mm gives me 5.3 mm thickness, .7 less than what Emisar uses. Though I’m not sure how should I scale the rim below the lens, so that may be somewhat incorrect. Anyway - it would be smaller but probably slightly less throwy because of catadioptic’s low efficiency. It would definitely be less efficient. If efficiency is not meaningful then yes, catadioptric may be an OK option.
I would like to understand. But so far I understand it exactly the opposite way. And none of these people has shown a hole in my justification.
So far the argument on my side was a simple calculation.
Arguments on the other side were:
Did I miss something?
I see some possible explanations on why nobody does it in practice. The biggest being:
There may be others, even bigger.
Yes.
“multi-optics don’t use whole frontal area”
If you add more emitters, and maintain lumen output the same, you can’t have more throw, because you are wasting part of your optic space.
If you add more emitters, and drive them all hard, you may end up with the same or more throw, at the cost of a lot of other issues, like more heat, decreased runtime, lower efficiency, etc etc etc.
Man. This is a forum for flashlight enthusiasts. Some of the people answering in this thread have forgotten more about flashlights than I have ever learned. If there was a reasonable way to get higher throw by using multiple emitters, they would know. Flashlight companies and enthusiast have spent a lot of time and money making the best throwers possible, for profit or fun, and they all share one common factor: Single output sourcer.
The very user who made the lens/reflector calculator that you quoted already answered and told you that adding more leds won’t increase throw. What else do you want? A 60 page report?
Go ahead, build a light and prove me wrong. God knows I would love to find a way to cram more candela into a smaller flashlight. I’d be happy to be proven wrong.
EDIT: Simple example:
Smaller emitters are better for throw precisely because they are small.
What is the point of having a small emitter if you then add many emitters?
We want the smaller possible emitter because that usually results in a higher cd/mm. If you add more emitters… you won’t get as high a lm/mm. You are holding onto edge cases and theoretical math, when practice, real life, and available products tell the opposite story.
I think there is some misunderstanding here. Agro is not saying you can increase the throw by using multi-emitters. He is saying you can theoretically get (very close to) equal throw as a single emitter, for a given head diameter, but this is not usually done because of wasted head area and not driving the emitters hard enough. A potential advantage of multi-emitters is that the head can be shorter due to the small reflectors.
I personally like to use multi-emitters so I can have a larger hotspot (more lumens) while still maintaining high beam intensity.
In case anyone is curious, I had short discussion about luminous efficacy with kaybi elsewhere, and he shared the raw data from his runtime test with me. Based on 5100mah from an average 3.7V battery, I made two calculations, depending whether you use Acebeam’s spec of 250 lumens, or kaybi’s measurement of 185 lumens.
Using 250 lumens yields 19.7 lumens/W
Using 185 lumens yields 14.5 lumens/W
This is very low compared to LED’s, but we’re talking about a fairly new technology, and downright crazy Candela/lumen numbers. It’s ridiculous to look at those beamshots and see that, while the BLF GT obviously provides further throw, that’s due to it’s significantly higher lumen output. The W10 appears to actually have a tighter beam, despite being far smaller.
Lumens have no effect on pure throw. The BLF GT throws further because its reflector has a much, much larger diameter compared to that of the lens in the Acebeam.
Did you use a fog machine to take those shots?
That looks sick.
I want a flashlight some day that looks like that but without any smoke/fog 
(hand held obviously, my syniosbeam already does that without smoke or fog 
)
This pic is useless without threads.
For max throw, aspheric lens lights are usually focused such that the lens projects a focused image of the die/light emitting surface. From what I’ve seen of the LEP it looks like there is non-emitting rectangle in the middle (used to block direct laser emission I’ve read), but I don’t see that in the beam. So what’s going on here? How is the lens focused?
Perhaps a combination of a recoil mirror and projecting lens?
The lens is probably out of focus and doesn’t project the image of the phosphor die.
EDIT : “High luminance at the laser light source provides valuable optical system advantages including narrow beam angle, sharp beam cut-off and smaller optical systems. Enabling beam angles smaller than 8 to 10 degrees from 25 to 50 mm optic diameter has been challenging with conventional light sources.
Utilizing laser light sources, beam angles of 2 degrees or lower have been demonstrated with total internal reflection optics of less than 30 mm in diameter, well within convenient lighting system form factor.”
”
Source“:https://soraalaser.com/wp-content/uploads/2017/09/LED-Professional-Article-Issue-63-2017.pdf.
From the same source : “In each of the two configurations, up to 500 lumens is emitted from a light emitting area only 300 microns in diameter resulting in luminance levels in excess of 1 billion cd/m²”.
= 1000 cd/mm²
Yes, LEP goes up to 3000cd/mm^2 (that is the highest value I have found). But not in a flashlight…
All you LEP experts, where is the light emitting surface in this picture?
It would be interesting if someone could take a picture of it through welding or eclipse-viewing glasses.
The absorption block is not at the light emitting surface, it is at the lens, which is significantly farther in front.
As the light rays spread out from the lens they cover up any hole that was created by the block.
You can only see the hole in the middle if the light is pointed up close, like a meter or less away.
If you eliminate the green triangle by blocking the center, the rest of the light will fill up the center hole after enough distance.
The entire yellow thing is the phosphor plate, but the laser is behind it and only the point at the very center emits light.
I think I see now, thanks. So could you use a hemispherical reflecting collar to increase efficiency and luminance?
Also, it seems like this LEP could be used in a traditional reflector, if the laser blocker was positioned correctly. Is this correct?
Yes and yes.
You would still need the blocking device attached to the regular lens on a reflector flashlight.
Also I’m not sure about how well it would perform with a reflector, the polar distribution may or may not be the same as a domeless LED.
There is no published data on the polar intensity distribution yet.
Try to focus that collar on a 0.1 mm² emitter….
It’s actually not as hard as it seems if you have a high contrast, because ambient light causes the collar to project an inverted image.
For example, a tiny black dot on a piece of paper.
The collar will project a shadow identical to the dot.
You know it is in perfect z-height focus when the shadow is as sharp as the original dot, and you know it’s in the right x/y position when the shadow is on top of the original dot.
