Olight SR90

[easilyled]

Don't get me wrong I am indeed impressed with the SST-90. Here's the thing. You cannot sustain the spec numbers for that SST90 in this light. I'm just making assumptions but I would fully expect that SST90 surface brightness figure come down pretty quickly to around 200. Now you can also easily overdrive the XR-E to 350 lumens per mm squared and sustain that in a light of this size. So the gap starts to widen.

I think that the enormous size of the SR90 might help against the lumens dropping too quickly.
I will await bigchelis's measurements.
Also, who's to say we can't still drive the SST-90 quite a lot harder.
Admittedly, the light would have to be huge or have active cooling in order to achieve it though.

 

[saabluster]

I think that the enormous size of the SR90 might help against the lumens dropping too quickly.
I will await bigchelis's measurements.
Also, who's to say we can't still drive the SST-90 quite a lot harder.
Admittedly, the light would have to be huge or have active cooling in order to achieve it though.

Yes you can over drive the SST-90 but you can also over drive the XR-E even more. How far do you want to go? The thing is that overdriving the SST90 will never meet the overdriven XR-E for surface brightness. It just won't happen. At 2.5A the XR-E was doing 450lumens. Do you think the SST90 will get anywhere near that on a surface brightness perspective before the die de-bonds? Now you must absolutely factor in real world effects. This Olight cannot even sustain these normal drive levels as is.

 

[stallion2]

LIGHT GOOD! DARK BAD!

 

[Dead_Nuts]

Surface area is exactly what I am referring to. That's why I said divide by 9.

SST90 @9A divided by 9(surface area)=244
XR-E R2 @1A (1mmx1mm) =270

The XR-E has more lumens per square mm= higher surface brightness.

So what we are looking at here is brightness/unit of surface area -- not total brightness of the emitter -- is that correct? That doesn't change the fact that the total surface output (in lumens) is greater on the SST90, right? Of course, throw is not just total lumens or even lumens/mm. Throw is generated, to some degree at least, by focusing the beam; either by reflector, lens(es) or both.

I guess I'm too dense to understand how an emitter that is over 8 times brighter than another can be out-thrown by the latter -- all other things being equal.

 

[saabluster]

So what we are looking at here is brightness/unit of surface area -- not total brightness of the emitter -- is that correct?

Correct

That doesn't change the fact that the total surface output (in lumens) is greater on the SST90, right?

Correct

Of course, throw is not just total lumens or even lumens/mm. Throw is generated, to some degree at least, by focusing the beam; either by reflector, lens(es) or both.

Correct

I guess I'm too dense to understand how an emitter that is over 8 times brighter than another can be out-thrown by the latter -- all other things being equal.

Imagine yourself as the reflector. What do you "see" when you look back at the emitter? Depends on what point you are at on the reflector. If you are at the very base right next to the emitter the LED die looks large. Since you, as a reflector, do nothing but relay the image of what you see forward the image you relay on will be a large one. As you move farther out to the rim of the reflector and look back the emitter will appear smaller. Therefore the image you relay on will be smaller.

The light leaving a reflector leaves at varying degrees of collimation based on how far away the reflective surfaces are and the size of the light source. The most collimized part of the beam comes from the part of the reflector farthest away from the source. The most collimized part of the beam forms the very center of the projected beam. As you move farther down the reflector(towards the source) the light that gets "collimized" into the projected beam will progressively move outwards from that center.

The reflector or even optic is no different than if you looked at yourself in the mirror. The mirror just relays information back to you. Blow up a balloon while standing in front of the mirror and you will see it get bigger right? You can also tell which LED die is larger when holding an XR-E and SST90 up to that same mirror as long as they are at the same distance. The beam from a flashlight is just a projected image. Increase the size of the thing being imaged and the resulting beam will be larger. If the thing being imaged is more red that is what will be relayed forwards. If it is larger then the projected image will be larger. If it is more intense then that is what will be projected forwards.

Here is a fun little trick that may help you to understand what I am talking about. Start with an LED light that has a nice smooth reflector. Now use some black electrical tape to block out all but a small part of the beam at the very edge of the emitting face of the light. It should be a little square section about an 1/8"th to 1/4" and symmetrical. When you turn on the light you should see a picture of the LED die projected against the wall. Now cover that area and make the same sized hole but closer to the center of the face of the light. You will notice the projected image of the die gets larger. This is because that part of the reflector is closer and "sees" a larger emitter. The resultant beam from that part of the reflector is less collimized, or less parallel.

Hope that helps some.

 

[windstrings]

You can get some of the same effect by simply looking straight into a reflector "with the light off" and you will see the die.
A good reflector shows all of the die providing your eyeball is within the path of the projected pattern.

I think I see what your saying but isn't what we are really talking about here is now many electrons are getting emitted?

The hotter the surface, the more are being released to get projected forward right?

Only problem is..... I would think the total number of electrons going forward is dependent upon "temp per square mm"....
Higher the temp... the more electrons you get from that single mm of area of space.

If the area of MM of the SR90 is close to 9 times, then if the surface temp was the exact same... it would stand to reason the SR90 has 9X the lumens projecting forward... but since its slightly cooler there is a difference..


I think the discussion is that the difference in less temp per sq MM the SR90 has in no way detracts from the nine times more surface area!

Even if the SR90 was half the temp of the other LED.... that would mean it only has to be double the size to make up for the difference right?... but its not.. its 9X bigger?

I don't know if we are dealing it exponents here.. but regardless of what LED you use, you have to capture all the light with the reflector or aspheric lens you use or it negates this whole discussion.

Projected light through an spherical lens is somehow much more efficient and polarized different than after it has to bounce and bend off of a reflector.

So when are we gonna make a DEFT with the SST90?

Talk about a light cannon! I"m sure the lens would have to be bigger.. but who cares!

 

[Mr. Tone]

I know this is slightly OT, but we are there already. Hopefully this analogy will help someone.

Imagine having two heaters, one smaller and one 9x larger. Let's say they are both exactly at 300 degrees F. temperature. All other things being equal the larger one will heat up any given space faster and more evenly(more flux). Let's say that we can raise the smaller one to 400 degrees but not the larger one(surface brightness difference). The smaller one now has the ability to raise the temperature of something in contact with it to a max of 400 degrees while the larger one can not raise the temp of something past a max of 300 degrees. No matter how you would position the larger heater or wrap it around something it could not heat something past 300 degrees.

I am sorry if my analogy doesn't make sense to anybody else because it does to me. It is also past my bedtime so take that into consideration.

I hope those of you with the SR90 keep chiming in here to tell us more about your experiences with it. It seems like a superb design and is exceeding all expectations. It appears to be a force to be reckoned with.:devil:

 

[easilyled]

saabluster, don't you think to some extent though, that even if an XRE throws a little further than the SST-90 (with both driven to the max), that there are diminishing returns on the usefulness of the beam as you widen the reflector?

For example in the Olight SR90, the reflector is probably at the optimum width for the SST-90 to really "shine", so to speak in terms of both throwing extremely well and also illuminating a wide enough area to have a lot of clarity about the scene that is illuminated.

Put an R2 XRE in there and overdrive it and yes, no doubt it will throw even further, but the beam will be like a pencil and not nearly as useful.
You would have to "wiggle" it around until you find the target and then you also lose perspective of the target's immediate surroundings.

Furthermore, there is a limit to how far the eye itself can see!

It seems to me that the way forward is to keep improving the surface brightness of these large, powerful single-die emitters so that housed in the appropriate optics, they will compete with the 50W Polarion and even more powerful HIDs than that.

 

[Mr. Tone]

That is what makes this SR90 so cool in my mind. They are able to push the LED to be really bright, not too far from an XR-E in brightness. Since it is really bright and huge the well collimated hotspot is bright, large and useful.

Another thing I am liking about the SST LED is that they have the same kind of beam pattern of an XP-E. I like the well defined hotspot and then completely even spill from there to the end.

 

[windstrings]

I know this is slightly OT, but we are there already. Hopefully this analogy will help someone.

Imagine having two heaters, one smaller and one 9x larger. Let's say they are both exactly at 300 degrees F. temperature. All other things being equal the larger one will heat up any given space faster and more evenly(more flux). Let's say that we can raise the smaller one to 400 degrees but not the larger one(surface brightness difference). The smaller one now has the ability to raise the temperature of something in contact with it to a max of 400 degrees while the larger one can not raise the temp of something past a max of 300 degrees. No matter how you would position the larger heater or wrap it around something it could not heat something past 300 degrees.

I am sorry if my analogy doesn't make sense to anybody else because it does to me. It is also past my bedtime so take that into consideration.

I hope those of you with the SR90 keep chiming in here to tell us more about your experiences with it. It seems like a superb design and is exceeding all expectations. It appears to be a force to be reckoned with.:devil:

I appreciate the word picture... I think that was pretty much true to life.

If you take those same heaters "small at 400 degrees and large set at 300 degrees and they are both infared and channel them both with a reflector that narrows the heat to 30 degrees and point one at a wall 100 feet away with a thermometer, the big heater will raise the thermometer higher than the small one.

True, if you stand right in front on either, the small will raise it higher because its set higher but being right in front of the emitter is not a fair test of what will happen in the distance.

Set an infared camera 1000 yards off in the distance, I would venture to say the large heater would register a much bigger signature than the smaller one running slightly hotter.

 

[saabluster]

If you take those same heaters "small at 400 degrees and large set at 300 degrees and they are both infared and channel them both with a reflector that narrows the heat to 30 degrees and point one at a wall 100 feet away with a thermometer, the big heater will raise the thermometer higher than the small one.

True, if you stand right in front on either, the small will raise it higher because its set higher but being right in front of the emitter is not a fair test of what will happen in the distance.

Set an infared camera 1000 yards off in the distance, I would venture to say the large heater would register a much bigger signature than the smaller one running slightly hotter.

I don't have time right now to give a proper response but before you head down this road any further let me just say don't. You are way off on your understanding of how this all works. I will come back later when I have time. I think this conversation needs to move out of this thread anyway so I will probably start it as its own thread and advise those following it here. No need to muck up the SR90's thread any further.

 

[windstrings]

Well I don't want it to be a sore spot, but I would like to understand this concept..... if you start in another place I would like to participate.

I understand laws of multiplication that says the hotter the more throw..... just now sure why laws of addition don't apply too that says, "More light equals more throw too".

Seems they both work together.

Sorry the discussion has hit a sore spot.. that wasn't the intention but rather to learn.

 

[dcycleman]

still no new beamshots???

 

[Mr. Tone]

Windstrings, have you done much more outside comparisons between the SR90 and the L35? Those beamshots were helpful and appreciated. Outdoors does the SR90 have the same throw, more, or slightly less than the hottest part of the L35 beam? Would you say the beam is pretty much the same pattern as a XP-E, albeit on steroids? How about the tint and color rendition, are you liking that, too?

 

[stallion2]

Well I don't want it to be a sore spot, but I would like to understand this concept..... if you start in another place I would like to participate.

I understand laws of multiplication that says the hotter the more throw..... just now sure why laws of addition don't apply too that says, "More light equals more throw too".

Seems they both work together.

Sorry the discussion has hit a sore spot.. that wasn't the intention but rather to learn.

i don't think SB is talking about absolute output or even beam manipulation after its left the emitter. he's talking about the concentration of light (output & area). the XR-E's create a better starting point cause they're only 1mm x 1mm (approx) and their total output is...lets just say 300lm over that area (i'm not sure if that figure is right but it should be close). if the SST90 is 3mm x 3mm then you have 2200lm created over an area of 9mm(^2).
the XR-E, at an area of 1mm(^2), is producing 300lm...multiply that figure by 9 to simulate performance over an area identical to the SST90 and your output would be 2700lm.

in addition to that the XR-E's have a viewing angle of 90 degrees vs the SST90's 100 degrees which allows the XR-Es to concentrate their higher output (factoring for the difference in area) farther down range.

but i have to agree w/ a loss in practical application by swapping in an XR-E, but thats really up to whomever owns the light and what they want to use it for. strictly for the purposes of maximum throw, the XR-E is still a better starting point than the SST's.

EDIT: it just came to me that the comparison works in reverse. take and SST90, running at its full potential and then cut off 1mm from every side. you'll be left w/ a piece of SST90 thats 1mm x 1mm and if the SST90 is pushing 2200lm at its full size of 3mm x 3mm then the 1mm x 1mm section is only producing 244lm.

 

[Dead_Nuts]

OK, but the SST-90 is the size that it is. It doesn't matter what would happen if you cut off part of it. I agree that is has 9x the surface area, but so what? If you could somehow focus all the output from this emitter into the same size and shape beam as an XR-E R2, wouldn't it have to 'outshine' it? In other words, wouldn't a beam of 2200lm out throw a physically identical 270lm beam? If so, what am I missing? Is it the fact that it's impossible to focus the larger die emitter to the same degree? I know that 'focus' is the wrong term here, but I'm no EE or physics major; just a guy who is intrigued by this discussion.

 

[windstrings]

Windstrings, have you done much more outside comparisons between the SR90 and the L35? Those beamshots were helpful and appreciated. Outdoors does the SR90 have the same throw, more, or slightly less than the hottest part of the L35 beam? Would you say the beam is pretty much the same pattern as a XP-E, albeit on steroids? How about the tint and color rendition, are you liking that, too?

Its really hard to compare the beam and technology is so different.

Its really hard to see, but the 35W HID has a tiny hotspot that is slightly brighter than the beam of the SR90. But the beam of the SR90 is so perfect, bigger and solid, it overwhelms what the 35HID could hope to do in its throw pattern at a distance.
Yes the 35HID will illuminate it, but the illumination is so fragmented that is harder to define objects in the distance compared with the even beam of the SR90.

The strength of the 35HID is the corona is bigger so in the distance you will view a larger area and the spill is brighter too... but with the SR90 the "shaft" of solid light it projects IMO is more usable in the distance because you still have enough spill to maintain perspective of surroundings but what you actually decide to illuminate with the shaft its totally bathed in a solid beam of light.

By my description it almost sounds laser like but its not because that 'shaft" is so big that its really more like the 35W HID funneled down to an even shaft of light that about 8 feet thick at 50 yards or so and maybe 50 feet thick at 150 yards or so surrounded by a very even soft spill.

Without me doing outside beam shots, thats the best I can explain it.

I think they chose a perfect beam as I like throw and any less condensed would kill throw and make it a good flashlight and any more condensed would be too tight becoming more like a Maxabeam spotlight type light that has limitations.

Have you even seen the movies where the prisoner is trying to escape, and he's out of the tunnel waiting for the spotlight to pass so he can make a run for it?
That type of spotlight "only" see's whats in its beam. The beam is so bright that it kills nightvision for anything not in the beam. Whereas the SR90 gives enough spill to reveal surroundings of object not in the direct path of the beam.

Maybe someone else who has the SR90 can add to what I've said.

 

[stallion2]

OK, but the SST-90 is the size that it is. It doesn't matter what would happen if you cut off part of it. I agree that is has 9x the surface area, but so what? If you could somehow focus all the output from this emitter into the same size and shape beam as an XR-E R2, wouldn't it have to 'outshine' it? In other words, wouldn't a beam of 2200lm out throw a physically identical 270lm beam? If so, what am I missing? Is it the fact that it's impossible to focus the larger die emitter to the same degree? I know that 'focus' is the wrong term here, but I'm no EE or physics major; just a guy who is intrigued by this discussion.

what you're suggesting should work, at least on paper. the math is there but i just don't know if we have the technology & materials that will allow for it yet. thats definitely a question for SB.

 

[easilyled]

OK, but the SST-90 is the size that it is. It doesn't matter what would happen if you cut off part of it. I agree that is has 9x the surface area, but so what? If you could somehow focus all the output from this emitter into the same size and shape beam as an XR-E R2, wouldn't it have to 'outshine' it? In other words, wouldn't a beam of 2200lm out throw a physically identical 270lm beam? If so, what am I missing? Is it the fact that it's impossible to focus the larger die emitter to the same degree? I know that 'focus' is the wrong term here, but I'm no EE or physics major; just a guy who is intrigued by this discussion.

You can focus the output from the SST-90 but you'll always need a larger reflector than you would for an XRE to achieve the same throw.

That is the point that saabluster was making.

It really doesn't matter though because there's a limit to how useful the beam is and I'm sure that if an XRE was in the Olight SR90 instead of the SST-90, the beam would not be nearly as useful even though it could throw a little further.

With XRE, think pencil beam instead of ram of light.

 

[easilyled]

Its really hard to compare the beam and technology is so different.

Its really hard to see, but the 35W HID has a tiny hotspot that is slightly brighter than the beam of the SR90. But the beam of the SR90 is so perfect, bigger and solid, it overwhelms what the 35HID could hope to do in its throw pattern at a distance.
Yes the 35HID will illuminate it, but the illumination is so fragmented that is harder to define objects in the distance compared with the even beam of the SR90.

The strength of the 35HID is the corona is bigger so in the distance you will view a larger area and the spill is brighter too... but with the SR90 the "shaft" of solid light it projects IMO is more usable in the distance because you still have enough spill to maintain perspective of surroundings but what you actually decide to illuminate with the shaft its totally bathed in a solid beam of light.

By my description it almost sounds laser like but its not because that 'shaft" is so big that its really more like the 35W HID funneled down to an even shaft of light that about 8 feet thick at 50 yards or so and maybe 50 feet thick at 150 yards or so surrounded by a very even soft spill.

Without me doing outside beam shots, thats the best I can explain it.

I think they chose a perfect beam as I like throw and any less condensed would kill throw and make it a good flashlight and any more condensed would be too tight becoming more like a Maxabeam spotlight type light that has limitations.

Have you even seen the movies where the prisoner is trying to escape, and he's out of the tunnel waiting for the spotlight to pass so he can make a run for it?
That type of spotlight "only" see's whats in its beam. The beam is so bright that it kills nightvision for anything not in the beam. Whereas the SR90 gives enough spill to reveal surroundings of object not in the direct path of the beam.

Maybe someone else who has the SR90 can add to what I've said.

I think its fair to summarize your explanation by saying that the hotspot in the Olight SR90 is much bigger.

Therefore at a distance of 500m, for example, the hotspot of the Olight SR90 lights up a much wider area at equal intensity, than the 35W HID.

I've just tried my Olight SR90 out in a nice big open space at the top of the hill which I'm perched on.

I love the beam distribution with the ram of light punching into the distance and the spill still lighting up everything in close and medium distance too.

The field-of-view that is illuminated is mighty impressive. No need to move the light around much. (which is probably just as well considering its weight!)