LED Selection
This page will help you select the best LED for your application
INFORMATION (click a heading to expand the section)
Beam Quality and Balanced Engineering

A good light is not just about more lumens, it's about having a well balanced package that is versatile in a varity of situations. My lights are designed for 80% of flashlight use cases, not the highly specialized 20% like a weapon light or search light.

The top four elements of a "quality" beam are: wide flood, smooth beam profile, good color reproduction, and usable power.

Wide Flood: If you follow the "80/20 rule," a floody beam is best for 80% of flashlight work. It's like camera companies trying to sell you more zoom when you really need wider angle. A highly concentrated beam is only good at one thing, distance, and if you are using the light up close that's bad. Every MCE and XML based light I make will throw light over 100m and provide a huge amount of flood.

Beam Profile: is the overall distribution of light within the beam. I insist that the beam have no dark shadows and a smooth transition from the center spot to the softer spill light. I tested nearly two dozen reflectors and optics before settling on the Ledil "Boom" reflector. Ledil is located in Finland and they only make one type of product...optics for LEDs. They really know their stuff. One of the most common pieces of feedback I get from customers (I'm paraphrasing) : "The Alpha has a better beam than any other light I've seen." Yep, that's the idea.

Color Reproduction: I say "color accuracy" and not "color rendering" because the latter is a technical term that can be measured by instruments. I also tested dozens of cool and neutral LED tints to select the ones that provide the most natural looking color at that particular temperature. LED lights have the reputation for ugly blue and purple beams, and that's because most manufacturers use the lowest possible quality (cheapest) LEDs. I only use the highest possible quality.

Usable Power: More power is not always better because it leads to shorter battery life and more heat. It's hard to explain the massive amounts of energy being released by these lights. People think LEDs "run cool" and that's just not the case at these power levels. You can find brighter lights but they are either much larger or will melt down in under 10 minutes. You can find lights that run longer but they are either much larger or they are much less powerful. The Alpha represents my ideal balance.

LED Options at a Glance
The spider chart and comparison table below help visualize your LED options at a glance.

Please see the next sections for detailed technical information and ANSI FL1 flashlight standards.

A lot of people write and ask what LED I recommend. Without question, I recommend the MCE 4500K Neutral White LED. If you are ordering a custom light you can select this option during checkout. All Ready-Made lights come with this LED.
  • Generally speaking, the MCE produces a beautiful beam and runs for 1.5 hours on maximum power.
  • The XML has more output, but it runs MUCH hotter and only gets 1 hour run time on maximum power.
  • The XPG is ideal for those seeking maximum color rendering and a warm beam that is the same as incandescent, but it's much less powerful than it's siblings.
 
ANSI FL1 Standards for Flashlight Testing

The American National Standards Institute (ANSI) released the FL1 standards for flashlight testing and reporting in 2009. The standard is voluntary, and adopted by companies committed to the accurate and responsible reporting of their products. These standards help consumers make "apples to apples" comparisons between flashlights.

ANSI FL1 should also help consumers feel more confident that they are getting products that perform as advertised. Many less reputable companies in the flashlight industry exaggerage their product claims, so please look for ANSI standards when purchasing a flashlight.

Light Output: Total lumens measured between 30-120 seconds of powering on the flashlight. A lumen measures the total quantity of light emitted, and does not indicate anything about how that light is distributed within the beam. For example, a street light puts out a lof of lumens but they are not very focused. A laser puts out very few lumens but the beam is highly focused.
Run Time: The length of "continuous" run time until the light output drops to 10% of the original value recorded. Please note that "intermittent" use will greatly increase the cumulative run time of a flashlight. The Alpha also has a low battery warning (light shifts to low and strobes once per second) that will activate at 3.2V. The light will be delivering more than 10% brightness at this time, but further discharge from this state may permanently damage the battery. The Alpha's run time is measured until the low voltage warning activates, not until 10% of original brightness.
Beam Distance: The distance in meters where the flashlight produces a light intensity equal to the illumination provided by a full moon on a clear night (.25lux). The value is calculated (based on peak beam intensity) because it cannot be effectively measured outdoors due to things like differing atmospheric conditions.
Peak Beam Intensity: Measured in candela, this is the brightest area of the beam measured at 1m...typically at the center. The candela is a unit of measure that replaces candlepower. This measurement should not be confused with light output (lumens). This value is used to calculate the maximum beam distance.
Impact Resistance: A light must survive a drop onto concrete from this height. In order to pass the test, the sample must be dropped on all 6 sides and the light tested for function after each drop. Cosmetic damage is not a factor in this test. This does not mean the light is guaranteed to repeated drops "in the real world" but rather that (on average) it is likely to survive.
Water Resistance: Measured in meters, this rating breaks down into three categories: water resistant IPX4 (splashing water), water proof IPX7 (submerged @ 1m for 30 min), and sumbersible IPX8 (submerged @ > 1m for 4 hours). Most hand-held flashlights have IPX4 or IPX7 ratings.
LED OPTIONS (click a heading to expand the section)
MC18-B (Cree MCE LED)
COOL WHITE (6500K)
NEUTRAL WHITE (4500K)

About the Cree MCE:

The MCE features 4 LED dies clustered onto one chip. This makes a very powerful light, but because of the large surface area, is best suited to "flood" applications. Generally speaking, the larger the emitter area, the "floodier" the beam.

The MCE is an older technology that the XML, but for a small hand-held light I think it's a superior LED. The XML is brighter, but it just can't beat the MCE for beam quaility and color accuracy. It also costs 3X as much as the XML and is one reason flashlight manufacurers are eagerly embracing the newer XML. I'd be happy to put that extra $10 in my pocket, but it just doesn't make a better flashlight.

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The MCE beam profile: (the image above is grey-scale to highlight variations in inensity)

A "good" beam profile means a smooth transition from hotspot to spill and no artifacts (shadows) anywhere in the beam. The MCE, coupled with the Ledil Boom reflector produces and ideal beam profile. In fact the "perfection" of the beam profile is one of the most frequently celebrated characteristics of the Alpha.

This type of "flood" beam is ideal for general purpose and indoor use. When researching lights, most people focus on lumens (brightness) and throw (distance). This might be fun, but it doesn't necessarily make the most usable flashlight. If you had to choose between a top fuel dragster and a BMW M3 as a daily driver, which one would you pick?

A floody light is better for 80% of general use and a throwy beam...the other 20%. For my money, I spend it on the 80% use case. The Alpha is intended to be the best flashlight, not the brightest.

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Comparing high, medium and low modes:

Most people think of mode selection as brightness selection. However, Isuggest that you also think of it as a battery management feature. Medium runs for more than 5 hours and still puts out ovewr 170 lumens.

On low (and in person) the low mode is plenty bright for indoor navigation and is effective outdoors to about 10 feet. High mode is ridiculously bright, especially indoors. Most of the time it's too bright...but it's there when you need it.

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Color temperature and color rendering (mouse over the image to alternate):

Most people think that LEDs produce a very cold blue or purplish light. This is true of low quality LEDs you find in inexpensive lights. My lights do NOT produce a blue/purple light because I request specific "tint bins" from my supplier. This also means the LEDs I use are considerably more expensive.

The scene above is lit ONLY with the MC18-B. There is no ambient light. The camera white balance is set to "daylight" mode.

Cool White (6500K)

The MCE produces an extremely crisp cool-white beam in the 6500K tint. The color accuracy is superior to the XML. If you are in the market for a perfect beam profile and lots of lumens, choose the cool MCE.

Neutral White (4500K) "MAKER'S CHOICE"

The neutral MCE is absolutely georgeous. I said it, georgeous. It provides excellent color rendering while chucking out a darkness-punishing number of lumens.

My theory is, over thousands of years our human visual systems have adapted to take advantage of the only light source available after dark...fire. Even a typical incandescent bulb produces the same color light as a candle.

It's only since the advent of the LED that we can produce daylight 6500K...at night...and my experience says that our brains have a harder time with object recognition and eye strain when using cool light at night.

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XM18-B (Cree XML LED)
COOL WHITE (6500K)
NEUTRAL WHITE (4500K)

About the Cree XML:

The XML is Cree's newest, most efficient, and most powerful LED. It features a single large LED die (as opposed the the 4 dies of the MCE) and has a smaller overall surface area. This means, coupled with the same Boom reflector, the XML will have a slightly brighter and more intense hot spot compared to the MCE.

The XML's efficiency has two drawbacks. First, increased heat. More efficiency means the LED can draw maximum current from the battery for a longer period of time...this translates to more heat. This also means the XML will drain your battery faster than the MCE.

Im practice, the XML is best suited to use cases that require short bursts of light rather than long continuous operation.

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The XML beam profile: (the image above is grey-scale to highlight variations in inensity)

A "good" beam profile means a smooth transition from hotspot to spill and no artifacts (shadows) anywhere in the beam. The XML (with Boom reflector) produces an excellent beam profile, but not as smooth as the MCE. The XML also has a center spot that is a significantly different color than the spill. This "tint shift" is observed in every XML-based light I've seen.

The XML does produce a noticably more intest hot spot, due primarily to the smaller surface area of the die. I would still consider this a "flood" type light but it's got little more punch than the MCE.

A floody light is better for 80% of general use and a throwy beam...the other 20%. For my money, I spend it on the 80% use case. The Alpha is intended to be the best flashlight, not the brightest.

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Comparing high, medium and low modes:

Most people think of mode selection as brightness selection. However, Isuggest that you also think of it as a battery management feature. Medium runs for more than 3 hours and still puts out over 230 lumens.

On low (and in person) the low mode is plenty bright for indoor navigation and is effective outdoors to about 10 feet. High mode is ridiculously bright, especially indoors. Most of the time it's too bright...but it's there when you need it.

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Color temperature and color rendering (mouse over the image to alternate):

Most people think that LEDs produce a very cold blue or purplish light. This is true of low quality LEDs you find in inexpensive lights. My lights do NOT produce a blue/purple light because I request specific "tint bins" from my supplier. This also means the LEDs I use are considerably more expensive.

The scene above is lit ONLY with the XM18-B. There is no ambient light. The camera white balance is set to "daylight" mode.

Cool White (6500K)

So, color rendering in cool white tint...did I mention the XML is really bright? If you want good color rendering, the XML is not for you. I'm not sure if anyone else will say this...but the color rendering of the XML is (in my opinion) really poor.

This is because the XML has a significant "tint shift" from the center of the beam to the edge. The center spot is the correct tint, surrouned by a yellow/green corona, and then tapering out to blue/purple at the edges. All XMLs exhibit this shift and it's most noticable in the cool tints.

Yes, you are detecting a hint of green. I don't want it to be there...but it is. This is a "1C" bin XML which is the "best" white tint bin that is readily available...and it's still green...just barely.

Neutral White (4500K)

The neutral XML is actually quite good in terms of color rendering and tint. However, you still get the "tint shift" at the edges of the beam. In practice it's less pronounced than with the cool white XML. If you need a little more oomf than the MCE can provide, I'm actually happy to recommend the neutral XML...if you can accept 50% less run time and way more heat.

Neutral LEDs are not as bright as their cooler bretheren, but the slightly warm tint is better suited to our night vision.

My theory is, over thousands of years our human visual systems have adapted to take advantage of the only light source available after dark...fire. Even a typical incandescent bulb produces the same color light as a candle.

It's only since the advent of the LED that we can produce daylight 6500K...at night...and my experience says that our brains have a harder time with object recognition and eye strain when using cool light at night.

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NC18-B (Nichia 219 High CRI LED)
NEUTRAL WHITE (4500K)


About the Nichia 219:

The Nichia 219 High CRI (Color Rendering Index) is specifically designed to deliver accurate color rendering to the human visual system. It is the most powerful High CRI LED on the market. On a scale of 1-100 it scores a 93+. The LED tint is neutral white and comes in a CCT (Correlated Color Temperature) of 4500K.

Unlike the more powerful cousins, the NC18-B uses a 1.4 Amp (vs. 2.8A) driver that provides double the run-time and can be operated indefinitely without concern for excessive heat build up.

This light is designed specifically for professional use. The NC18-B is an ideal choice for people whose lives and/or jobs depend on superior color rendering accuracy. A few examples include outdoor chefs, fashion designers, interior designers, doctors, EMT's, photographers, wildlife biologists, film makers, aircraft mechanics, airline pilots, building inspectors, contractors, crime scene investigators, detectives, etc.

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The Nichia 219 beam profile: (the image above is grey-scale to highlight variations in inensity)

A "good" beam profile means a smooth transition from hotspot to spill and no artifacts (shadows) anywhere in the beam. Again, the Boom reflector and the Nichia 219 produces an excellent profile. The hotspot is quite small because of the small surface area of the 219's die. However, the 219 is driven at 1/2 the current (Amps) compared to the MCE and XML. This means less intensity and fewer overall lumens. I still consider this a "floody" light.

A floody light is better for 80% of general use and a throwy beam...the other 20%. For my money, I spend it on the 80% use case. The Alpha is intended to be the best flashlight, not the brightest.

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Comparing high, medium and low modes:

Even though the NC18-B is the least powerful light in my lineup, it's still brighter than 95% of readily available flashlights. The main advantage (besides color rendering) is that this light will run for 2 hours on high, and will never get too hot to hold, because the LED is only driven at 1/2 the current of the MCE or XML.

You can also grill a steak in the back yard and tell what it actually looks like. I don't know if you've ever tried to check your rib eye while wearing a headlamp (extremely cold color) but it makes your hard work look like zombie meat. Fun at halloween but not good when you are trying to tell the difference between medium and medium-rare.

This light is also intened for close-up work where excessive brighness can actually be a handicap.

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Color temperature and color rendering:

Neutral White (4500K)

The scene is lit ONLY with the NC18-B. There is no ambient light. The camera white balance is set to "daylight" mode.

The Nichia 219 is truly a stunning LED. Once you try it, it will be hard to go back to anything else. Your brain might not be able to tell the difference by reading my words, but your eyes will be amazed every time you turn this light on. If you demand the best color accuracy and don't care about insane output, this is an excellent choice.

While this is an unusual color temperature for an LED, you'll become accustomed to the different tint in a couple of days. These beamshots look a little "brown" but in person, you can tell the color accuracy and vibrance is quite high. If you are considering the Nichia 219 High CRI; congratulations, you're officially a flashlight geek :)

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All Prometheus Lights ratings are based on ANSI FL1 Standards
 
MCE
6500K
(cool)

750L

1hr:30m
4hr:00m
15hr:00m
118m 3500 cd 2m

100m

MCE
4500K
(neutral)

600L

1hr:30m
4hr:00m
15hr:00m
109m 2900 cd 2m 100m
XML
6500K
(cool)

800 L

1hr:00m
3hr:30m
11hr:00m
158m 6200 cd 2m 100m
XML
4500K
(neutral)

750 L

1hr:00m
3hr:30m
11hr:00m
127m 4000 cd 2m 100m
Nichia 219 HCRI
4500K
(neutral)

250 L

2hr:15m
7hr:15m
40hr:45m
96m 2300 cd 2m 100m
Click any LED image (left) to open the "LED Options" tab associated with that LED

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