Why are LED's the future?

A visit to the surefire store has me wondering exactly what is happening to the torch industry. Is the future in LED's vs. Incan? I simply don't get it, yet.

For example, do you guys have problems with night vision loss and depth perception loss. Example: I am walking down a dirt road and come upon a puddle of water. With 70 lumen LED, the water seems less than 1" deep. So I take a step forward and woosh...more than ankle deep in water. This angers me.

Anyone following this line of logic or am I simply not used to using the LED lights.

sorta weird to agree since i use LED's now almost exclusively, but i do agree with an incan's more natural rendering. the tint is one factor that makes some LED's better then other's in rendering depth, and distance, but like one of our more learned CPF'ers said in one thread, the sun is not "white" it's yeallow'eque hue is probably what our eyes are primordially acustomed to. Incan's just seem to be a lot better at what you describe. (imho) VDG

The sun is an incandescent source, yes, but it's far from yellow. Just hold up even the whitest incandescent side by side next to the sun and you'll see what I mean. 5500K versus 3500K. At best the incandescent will look yellowish-orange.

I think part of the problem here might be simply that the beam pattern is different for LEDs versus incandescents. Incandescents usually have a very bright center area surrounded by a corona of gradually decreasing brightness. LEDs are also brighter in the center, but their hotspot is usually way less intense than an incandescent of similar lumen rating. That means less penetration in things like puddles. Also, incandescent beams usually have more artifacts as well as a slight hole right in the middle of the brightest part of the beam. These artifacts sometimes help to pick up more details as opposed to the smoother beam of an LED, or maybe most people are just used to them and anything else doesn't look quite right.

As to color temperature differences, to me anyway LED just seems more natural, at least in an urban environment with lots of neutral colors, or even with foliage which it renders as true green instead of the yellow green it would appear under incandescent. Whites? Again, no contest. They look white under LED, yellow under incandescent. Reds are the main weak point of LEDs but I imagine that deficiency will be overcome while still allowing a sunlike color temperature.

If you want to get technical, then the spectrum of most white LEDs peaks in the blue area, and again in the yellow area. It is weak in deep red and deep violet, and sometimes a little weak in the yellow-green area. Incandescents are rich in reds but progressively more deficient in greens, blues, and violets. The sun is more or less balanced across the entire visual spectrum, with a peak at 555 nm. Certain types of metal halide and fluorescent lamps can come close to this ideal, but none so far have been able to match it exactly.

Also, LED flashlights use a wide variety of focusing methods, and their beams are not well characterized by a single parameter like lumens. For example, my Surefire L4 puts out 70 lumens, but I have a 30-lumen LED flashlight (the Streamlight 4AA Propolymer Luxeon) that puts out a beam that is much, much more piercing and far-reaching due to a better focusing system.

jtr1962 said:

The sun is an incandescent source, yes, but it's far from yellow. Just hold up even the whitest incandescent side by side next to the sun and you'll see what I mean. 5500K versus 3500K. At best the incandescent will look yellowish-orange.

I think part of the problem here might be simply that the beam pattern is different for LEDs versus incandescents. Incandescents usually have a very bright center area surrounded by a corona of gradually decreasing brightness. LEDs are also brighter in the center, but their hotspot is usually way less intense than an incandescent of similar lumen rating. That means less penetration in things like puddles. Also, incandescent beams usually have more artifacts as well as a slight hole right in the middle of the brightest part of the beam. These artifacts sometimes help to pick up more details as opposed to the smoother beam of an LED, or maybe most people are just used to them and anything else doesn't look quite right.

As to color temperature differences, to me anyway LED just seems more natural, at least in an urban environment with lots of neutral colors, or even with foliage which it renders as true green instead of the yellow green it would appear under incandescent. Whites? Again, no contest. They look white under LED, yellow under incandescent. Reds are the main weak point of LEDs but I imagine that deficiency will be overcome while still allowing a sunlike color temperature.

If you want to get technical, then the spectrum of most white LEDs peaks in the blue area, and again in the yellow area. It is weak in deep red and deep violet, and sometimes a little weak in the yellow-green area. Incandescents are rich in reds but progressively more deficient in greens, blues, and violets. The sun is more or less balanced across the entire visual spectrum, with a peak at 555 nm. Certain types of metal halide and fluorescent lamps can come close to this ideal, but none so far have been able to match it exactly.

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I know little of the science of the sun and it's light, and yellow-orange I do agree since I did mention to my eye (and thousands of descriptions, in written literature over thousands of yr's) the sun is not "white" it's yeallow'eque hue" , orange is close enough, so agreed.

But i must respectfully disagree that the the beam or "hot spot has anything to do with difference in LED Vs incan. Other then the lumen or power the light put's out there is too many different LED and incan beam pattern's to blanket a statement as "Incandescents usually have a very bright center area surrounded by a corona of gradually decreasing brightness" although i do
agree a good Lux tint is better at color rendering but a overly green, yellow, or blue LED is imho, to my eye,, worse then a quality incan. VDG

voodoogreg said:

I know little of the science of the sun and it's light, and yellow-orange I do agree since I did mention to my eye (and thousands of descriptions, in written literature over thousands of yr's) the sun is not "white" it's yeallow'eque hue" , orange is close enough, so agreed.

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The sun is considered a "yellow" star on the Harvard classification system but that's only in comparison to other stars. Next to an incandescent its light would look quite white. It was the incandescent which I said would look yellow-orange when compared to the sun. Try it one day using your whitest incandescent. You'll be surprised how much whiter the sun is unless you do your experiment near sunrise or sunset. The sun's surface temperature (5500K) is about the same temperature as a welder's arc. At best you'll get an incandescent lamp to 3500K at the expense of a lifetime lasting only a few hours.

But i must respectfully disagree that the the beam or "hot spot has anything to do with difference in LED Vs incan. Other then the lumen or power the light put's out there is too many different LED and incan beam pattern's to blanket a statement as "Incandescents usually have a very bright center area surrounded by a corona of gradually decreasing brightness" although i do
agree a good Lux tint is better at color rendering but a overly green, yellow, or blue LED is imho, to my eye,, worse then a quality incan.

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Sure there's plenty of variations in beam patterns. I'm going by the types of incandescents most of the general public is familiar with, and those mostly have beam patterns with lots of artifacts. Let's face it, few people have even heard of SureFire, for example. When you say flashlight they think in terms of a Maglight. Yes, an off-tint LED looks horrible to me too, but then again to me all incandescents have a horrible yellow-orange tint to them other than the ones with blue filters. Back in the days when incandescents were my only choice for lighting things, I always used blue filters to get rid of the tint. After a while I just gave up on lighting things until LEDs came along because of problems like heat, short life, excessive power consumption, etc.

While I can understand not liking the worst LED tints, to answer the original poster's question they are the future precisely because their advantages far outweigh their drawbacks. I can light an HO passenger coach with four LEDs costing $1 total now and using 1/8 of a watt. The light looks just like I want it to, the LEDs will never burn out, don't need a filter, and they'll take 10,000 hours at least to get noticeably dimmer. When I used incandescents the bulbs cost several times as much, required blue filters most of the time (unless I was modeling really old rolling stock where the incandescent "look" was correct), used several watts of power, caused heat problems, and burned out often enough that I just gave up after a while. Colored LEDs where appropriate use 5% or less of the power of their incandescent counterparts. I could go on, but I think you get the idea. Let's face it, incandescent was hardly ever an ideal light source. Sometimes I think a lot of the comments here about the inferiority of LEDs are just plain nostalgia for incandescents. LEDs are far from perfect, but then again what is? They're better than anything else for small lighting needs at this point, and they're still on a steep improvement curve. Incandescents on the other hand reached their potential long ago. There's been little real improvement now in any parameter for quite a number of years.

That is some interesting data on the sun. I guess this is why we all have preferences on any kind of light. couple of thing's to keep in mind though,

the human eye differ's in everyone, this is a fact, ( my eye dr is my cousin)
how much light, color, Periphery, night vison etc. I would imagine this goes into yours mine and others thus personal preference. I read one post of a person that that doesn't like the new ARC AAA-P because of the blue tint, he said it Literally hurts his eyes and/or causes him a headache.

I know I have poor night vison, one reason i think i got into FL's, i always carried one around since childhood. VDG

In my industry we work to create daylight color tempature all the time.

You want light?
look here: http://www.lightningstrikes.com/lightningstrikes.html

No these are not led's.
LEDtechnology has made very slight inroads into the motionpicture biz. LED lighting is mostlty used for eyelights. Close up ring lights are used semi often .

DayLight Light in the motionpicture industry is extremely important most pictures are lit with lights that create daylight(5600K) light. It is going to be a while before LED's replace the kinds of lights we use today.
Yaesumofo

I couldn't find a night shot, but the spire here is covered in incandescent white LED A-19 bulbs.
http://thejoekorner.quuxuum.org/nyctbmt/stillwell/P0014743a.jpg
For weeks since they first went on, I was trying to figure what they were. Compared to the bright amusement lights across the street, they looked like a dim orange; not quite like a dim incandescent (which is a bit more reddish), but more comparable in color to the dull high pressure sodium color. It made me wonder if they may have been neons, or some kind of compact flourescent. However, the light still had that sharp LED look to it, despite the dimness. So I wondered perhaps amber LEDs, with the color dulled by the transucent white bulb envelope. And the bulbs looked smaller and rounder from a distance. Even at that size, incandescents are brighter and more yellow/tan-white.

Just last week I discovered some down above an entrance, almost in reach, and it was clear that they were really incandescent colored A-19's. IT was the dimness against the other light that made them look so orange. And now, since I had seen some incandescent colored (2500K) LED's when I went to the showroom look at the Dingdotz, I could imagine that a cluster of those placed in a bulb, and used outside would look like that. They looked so much like the light of small incandescent bulbs inside, but outside those same LED's, even in a cluster would be dim and orange looking. So now I realize I had been seeing incandescent colored LED's for a while before I saw the ones in the showroom.

Just by looking at the lumens of many LED bulbs online, I see that they are all very dim. (and yet some still cost hundreds!) With all the bright arrays being used in signs and signals, you wonder why they can't make bulbs brighter.

The sun is more or less balanced across the entire visual spectrum, with a peak at 555 nm.

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The sun is considered a "yellow" star on the Harvard classification system but that's only in comparison to other stars.

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A science Q&A website adressing "why are there no green stars" http://curious.astro.cornell.edu/question.php?number=14 says that the sun is really a yellow-green star (and 555 is yellow green). It explained why it doesn't look green. It's the same reason that in the Kelvin scale, it goes from red to yellow, to WHITE to blue. Green is in the middle of the spectrum, and the eye is most sensitive to it, so you see all of the colors, and it appears white. Part of the sun's looking yellow instead of pure white may also have to do with the blue sky, and the angle the light is coming to us at (the color drops the greater the angle, hence the orange sunrise and sunset).

EricB said:

Part of the sun's looking yellow instead of pure white may also have to do with the blue sky, and the angle the light is coming to us at (the color drops the greater the angle, hence the orange sunrise and sunset).

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Yes, both of those things are factors. At high noon when the sun is directly overhead the sun's color temperature is around 5500K. An hour before sunrise or sunset it's around 4000K (because the longer path through the Earth's atmosphere absorbs more blue than red). Right at sunrise or sunset I think it's roughly 3000K, or similar to a halogen lamp.

The sun also looks yellow in contrast to the blue sky. I once demonstrated this effect to myself very vividly when looking a one of my HO passenger cars lit with BestHongKong pure white LEDs which are roughly 5000K color temperature. When the room was dark they light looked more or less very white. When I turned on a small halogen desk lamp nearby the lights suddenly appeared bluish as my brain autocolorbalanced for the yellowish halogen. When I shined one of my home-made LED bike lights with very blue tinted white LEDs the light actually looked yellowish. In fact, suddenly switching the ambient light source between the halogen desk lamp and my LED bike light made the light in the train appear bluish and then suddenly appear yellowish within seconds. It was really an amazing demonstration of how white is really relative. Undoubtedly the blue sky makes the 5500K sun look yellow. However, when sun rays shine into a darkened room lit only by incandescents they appear white or even bluish-white.

randman said:

A visit to the surefire store has me wondering exactly what is happening to the torch industry. Is the future in LED's vs. Incan? I simply don't get it, yet.

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The reason most people believe the future lies with LED's is two-fold:
- LED's are more durable and last longer than conventional incandescant
lights
- LED's are more efficient--particularly at lower bright levels--than
incandescent lights

The reasons you don't yet see LED's totally dominating the flashlight world are:
- Bright LED's capable of producing 40 lumens or more are very expensive
to produce, especially in a neutral white color
- As brightness climbs, efficiency decreases, so the runtime advantage of
LED's is much less substantial at, for example, 60 lumens than at 10
lumens

As manufacturing processes for LED's are refined and costs decrease, I expect that incandescant bulbs will disappear in flashlights. Eventually, they will even disappear in household bulbs (though that may take a while yet).

It is harder to get a "natural" looking light from an LED since they don't really behave like blackbody readiators and tend to emit in narrow bands of frequencies rather than across a broad spectrum. Also, it can be harder to focus LED's--especially physically larger LED's that produce a lot of light--which could explain your problem with judging puddle depth.

- Jared

The sun also looks yellow in contrast to the blue sky. I once demonstrated this effect to myself very vividly when looking a one of my HO passenger cars lit with BestHongKong pure white LEDs which are roughly 5000K color temperature. When the room was dark they light looked more or less very white. When I turned on a small halogen desk lamp nearby the lights suddenly appeared bluish as my brain autocolorbalanced for the yellowish halogen. When I shined one of my home-made LED bike lights with very blue tinted white LEDs the light actually looked yellowish. In fact, suddenly switching the ambient light source between the halogen desk lamp and my LED bike light made the light in the train appear bluish and then suddenly appear yellowish within seconds. It was really an amazing demonstration of how white is really relative. Undoubtedly the blue sky makes the 5500K sun look yellow. However, when sun rays shine into a darkened room lit only by incandescents they appear white or even bluish-white.

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Oh well, then, let's talk about a real train system. In the NYC Subway, they are changing all the signals to LED, and certain signals that have a speed time mechanism have an additioanl aspect that uses 8000+K LED's (arranged as digital numbers for the speed) that are basically that almost lavender tinted white. But next to the red or yellow, the display looks straight up cyan! Closer, and you see it is a white with a strong blue "air"/"aura"/"halo", [whatever] around it; almost as if it was blue LED's. The white LED Christmas lights (forever Bright) I have are the same color, and when in the wondow behind the blinds in the dark, it looks almost exactly like daylight without the sun (cloudy day, etc), but other times, they can look lavender or pure white.

I went thru the same problem last Christmas. I walked thru a large puddle of water with a 2 LED flashlight. Later on I bought a 30 lumen "Streamlight 4AA Propolymer Luxeon" and got a better deal with that! Now, I can see where the heck i'm going when I go for a night walk"! My suggestion to those who take a night stroll is to get a LED flashlight with a lot of LED's in it or one with a good reflector!

Some comments:

- Compared to incans, most LEDS are much "whiter", with significantly more blue content. That does hurt your night vision as your iris responds predominantly to the blue end of the spectrum, not to the red.

- In term of color rendering, most cool white LEDS are in the 70-75 range compared to close to 100 for incan as they are like a blackbody source. That said, many prefer the color rendering of a cool white LED as it makes certain colors, i.e. the blues, and greens appear more like what you would see under sunlight, however, reds, etc. can looked washed out.

- You can get pretty good color rendering and almost blackbody light output from a LED. Try a Luxeon Warm-white with a CRI of 90+ and close to halogen color temperature. They are only about 1/2 as efficient as regular luxeons though. You can achieve a similar effect by adding yellow and red to a regular luxeon, and you can even play with filter on a regular luxeon to get a better Color rendering index.

- A puddle (being water) may also have some interesting characteristics that are better served with a warmer color temperature. However, when I am doing work around the house, I far prefer my LED flashlights as I find the visual acuity far superior. Part of that is a wider more consistent hotspot. With my incan flashlights, I find my eye is overwhelmed by the bright center spot and I can not see much else. I do know that my LuxeonIII Dorcy (tightest spot of my LED flashlights) cuts through water pretty well, but unless you have the angle right, it has more glare off the water which I expect is a function of more light off center compared to my incan and possibly different reflection\refraction of the higher light frequencies (blue, etc.)

Semi-Man

Let me start by saying that I love LED technology and am very happy to see it developing. As a frequent backpacker/camper I'm overjoyed at the notion of a light where you don't have to change the bulb and a drop doesn't mean a pop. I also like the long life of the emitters, but am troubled by the current trend of less and less lifespan in the more powerful units.

-I like the higher efficiency and battery life and the fact that most LED's don't just die, they drop to moonlight mode and you still get a lot of time to find your other batts and put them in. As the available power goes down the LED's actually get more efficient (the opposite is true for incandescent).

But all is not exactly perfect in LED land.

-I don't like blue/bluish LED lights (I'll take those slighty green tinted luxeons over the really blue ones). They always make my eyes feel like they are struggling to see (like there is some component of the light that is missing and my eyes are fighting to find it or compensate). The practical upshot is that my depth perception goes to hell and with a couple of severely blue lights it has made me dizzy.

I have heard rumors of "warm tone" LED emitters coming out that are supposed to cover more of an incandescent light range. I haven't seen any yet but look forward to seeing if they would solve my issue.

-LED lights (especially white and blue ones) seem to share one charistic with lasers...they tend to bounce around in water and/or water vapor. The result is that an LED light tends to illuminate a bank of fog or mist as opposed to cutting through it. The SOLE exception to this that I have personally seen is the new River Rock lights with the Jupiter LED and the focusing lens. That light does actually try to cut through although I have no idea why it should be the exception.

zespectre said:

I have heard rumors of "warm tone" LED emitters coming out that are supposed to cover more of an incandescent light range. I haven't seen any yet but look forward to seeing if they would solve my issue.

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Lamina has a 4300K warm white with a CRI of 90. That might be just what you're looking for. I personally haven't seen it yet so I can't say one way or another if it makes things look more natural.

BTW, the red deficiency of LEDs mentioned several times in this thread is not a function of the color temperature of LEDs as is often mistakingly thought. After all, we have 5500K fluorescents with almost perfect color rendering. It's simply easier at this point in time for LED manufacturers to get better color rendering if they also lower the color temperature. Eventually you'll have LEDs of all color temperatures which get good color rendering.

-LED lights (especially white and blue ones) seem to share one charistic with lasers...they tend to bounce around in water and/or water vapor. The result is that an LED light tends to illuminate a bank of fog or mist as opposed to cutting through it. The SOLE exception to this that I have personally seen is the new River Rock lights with the Jupiter LED and the focusing lens. That light does actually try to cut through although I have no idea why it should be the exception.

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I honestly don't think any light can really cut effectively through a mist so much as penetrate somewhat more into it. Probably any difference has to do with the peak intensity of the beam. That central hotspot on most incandescents will penetrate further and the relative lack of sidespill will tend to illuminate the fog bank less. You might test your theory about light color having something to do with it by comparing LED flashlights with identical optics but one with a warm white emitter and the other with a cool white emitter. My guess is you won't find much difference.

zespectre said:

I have heard rumors of "warm tone" LED emitters coming out that are supposed to cover more of an incandescent light range. I haven't seen any yet but look forward to seeing if they would solve my issue.

.

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Perhaps a bit more along than just rumours, "Warm white" Luxeons with a CRI of 90 ish have been around for at least a year. They are not as efficient as the lower CRI ones, but certainly they are tuned to behave more like incan coloration.

I don't know a whole lot about LED's in general but I have noticed that while using my LED lights out doors, specifically my PT EOS and SF KL1 that I do not have the depth perception like I have with an incandescent. This also applies to puddles and holes as the beam is so smooth that I can't tell what I'm walking into. I do like them for certain applications and for here in the city I use them more often, but I still can't replace incandecents with them just yet.