PDA

View Full Version : Flashlight brightness technology

JimL
November 8, 2009, 12:41 AM
Does anybody have a handle on candela versus lumens?

"Out there" I see the brightest defense flashlights rated at 150 or 200 lumens.

Today I saw a defense flashlight rated at 12,000MCD that hurt my eyes.

According to converting calculators I have found, 150 lumens converts to about 6.3 million MCD - well over 500 times as bright as the above flashlight.

Working the other way the 12,000 MCD light calculates out to about a quarter lumen.

This makes no sense whatsoever unless looking at the 150 lumen flashlights advertised is something similar to looking at the sun.

Apparently MCD essentially refers to the intensity of light in a point source (best I can tell), while lumens refers to the amount of light covering, in this case, a circular area. But the technicalities don't help. I'd like to know how the 12,000 MCD light compares to a 150 lumen light and I see no way to find out other than to buy them both and aim them on a wall or something.

Any explanations?

Thanks

November 8, 2009, 10:30 AM
Well, this is one of those things that there is no easy conversion factor. The candlepower is almost not used anymore, and it did refer to actual candles. I will give you a rough comparison. My Streamlight Ultra Stinger is rated both ways by Streamlight. It is rated at 75000 candlepower and at 295 lumen's. Now here is the problem. You cannot use this as a direct conversion because lumen's is greatly effected by reflector shape, surface of reflector, emitter, etc. Just use lumen s's as your rough reference. A light that has 80 lumen's will be brighter than one that has 45 lumen's, but if the 45 lumen light has a larger head it might give more throw (distance) than the 80 lumen light.

I'd like to know how the 12,000 MCD light compares to a 150 lumen light and I see no way to find out other than to buy them both and aim them on a wall or something.

From my example I would say the 12000 MCD is the brightest by far. I read 12000 MCD as 12000 X 10 to the 6 candle power.....and that's a big number.

I see no way to find out other than to buy them both and aim them on a wall or something.

Yes, in the flashlight world that's still one of the best tests you can make.

Lumen's is a useful reference when buying a light, but just remember there are other variables.

http://en.wikipedia.org/wiki/Candela

If the source emits light uniformly in all directions, the flux can be found by multiplying the intensity by 4π: a uniform 1 candela source emits 12.6 lumen's.

But I don't think that works out in the real world. I think if you use a light meter you will not even get close to that answer.

Like you said, just aim the light on a wall and compare.

Added: I notice in shopping that even HID (High Intensity Discharge) lights are rating in Lumen's. Many are rated in the 3500 lumen range. Look at one of those and you probably would not see for a week or so! If you can just stick to lights rated in Lumen's than you get a fairly good apples to apples comparison.

JimL
November 8, 2009, 08:12 PM
From my example I would say the 12000 MCD is the brightest by far. I read 12000 MCD as 12000 X 10 to the 6 candle power.....and that's a big number.
Hm. Something I read said MCD means millicandela and/or megacandela. I guess some disciplines use milli to mean divided by 1000 while others use it to mean multiplied by 1000. Confusing. I can pretty much guarantee you 12000 MCD doesn't mean 12,000,000,000 candle power. It's brighter than any of my other LED lights, but not that bright. My neighbor has a spot light that is 50,000,000 candle power and this light is a very tiny fraction of that.

And it would be odd if the 12000 MCD was the brightest of the two. It sells for \$25, while the 150 lumen sells for \$150. More confusing. I bought the 12000 MCD light today at a gun show. I tried to compare it to my regular 3 D cell maglight. Really impossible by eye given the color of the light, but they were fairly close, with the 3 cell probably a little brighter.

I'm not 100% convinced that the manufacturer knows what it means.

November 8, 2009, 08:54 PM
And it would be odd if the 12000 MCD was the brightest of the two. It sells for \$25,

OK, I am probably wrong on the units. I read that the capital M was meg and the little m was milli, anyway you are not going to beat 150 lumen's for \$25.

I bought the 12000 MCD light today at a gun show. I tried to compare it to my regular 3 D cell maglight. Really impossible by eye given the color of the light, but they were fairly close, with the 3 cell probably a little brighter.
Yeah, MCD must be milli. I can beat any 3 "D" incandescent Mag with just a 3 watt LED.

I go back to my Streamlight. 75000 candle power is about 295 lumen's. So that's about .004 lumen's per 1 candle power.

The fact is that 150 lumen's is pretty good. The old standard for years was a 3 "D" Maglight at about 45 lumen's, so we have come a long way. I think the best hand held lights are LED lights. I have a palm size Surefire with a Cree R2 LED that is about 230 plus lumen's. I am getting ready to upgrade my Wolf Eyes light to a Cree LED and Turbo head that will give about 280 lumen's. If you look on the flashlight sites you can buy up to about 400 lumen's LED for less that \$100. Another good choice is a Life+Gear LED at Target for about \$39 that has 210 lumen's and runs on 2 "C" batteries.

Try this site. I have purchased several things from them with good deliver and reliability.

http://www.lighthound.com/

and

http://www.batteryjunction.com/

johnson_n
November 8, 2009, 11:29 PM
Candlepower is the measurement of how bright it is at one spot (think spotlight or laser pointer).

Lumens is total light output.

If you've ever used SureFire or any lights like that, a 60 lumen two cell vs a 500 lumen 6 cell (SureFire M6 for example) both have the same brightness but the M6 puts out much more light.

There's really no way to compare CP to Lumens. And even then, different companies use different ways of measuring their output. Most measure by bulb lumens, SureFire measure theirs after the reflector (actual real world use).

November 9, 2009, 03:25 PM
If you've ever used SureFire or any lights like that, a 60 lumen two cell vs a 500 lumen 6 cell (SureFire M6 for example) both have the same brightness but the M6 puts out much more light.

Can't agree on that. I have the SureFire G2 (6v) that originally had the 60 lumen incandescent lamp. That is not the same lamp that the M6 (18V) uses. The M6 bulb is in fact much brighter. Runs on much higher voltage and current (watts) so it's not an apples to apples comparison.

But I do agree that CP is out-dated and best to use lumen's.

ZeSpectre
November 9, 2009, 03:50 PM
Candlepower is the measurement of how bright it is at one spot (think spotlight or laser pointer). Lumens is total light output.

I like to use the "hose" analogy.

A hose emits water, a flashlight emits photons.

If you have a hose it has a maximum capacity of water (Gallons per minute) that it can emit. HOW it emits that water is greatly dependent on the shape and size of the nozzle.

A very large nozzle with a lot of tiny holes "sprays" water in a wide pattern that doesn't have a lot of force and thus doesn't go very far. A small, focused nozzle with just one hole can throw the stream of water very far, but doesn't cover a lot of area.

A firehose, capable of handling a LOT more water at a time, will overcome some of the limitations, but will require massive pumps and a HUGE supply of water to operate.

One funny thing is that the "head size" on flashlights works opposite of a hose nozzle. The bigger the head on a flashlight, the bigger the reflector you can install and the better you can capture and re-aim all those pesky photons into one beam headed in one direction (THROW over distance but tight beam not a spotlight). A smaller and shallow head tends to be better for "floodlighting" but not so great for throw over distance.

Different tools for different jobs.

One thing I do know at this point. My personal opinion is that any light capable of more than 70 lumens should have a "hi/low" switch to take it down to about 15-20 lumens for "close in" work like reading a map at night!

JimL
November 9, 2009, 03:58 PM
There's really no way to compare CP to Lumens. And even then, different companies use different ways of measuring their output.
Different ways indeed. I doubt half of them know what their claims mean.

Another thing. I'm attempting to compare two lights, one rated in MCD and one rated in lumens. Bad enough in the first place. Now several of these posts are talking candle power - which we aren't even sure the manufacturer knows what it means, and if he did how would the references here to candle power help me with MCD's? Maybe 1 MCD (per this maker's usage) - one candle power? I'm sure I don't know.

If MCD is really millicandela, and the maker reports at 12000 MCD why didn't he just say 12 candela? Oh, excuse me - 12 isn't as impressive as 12000. Madmag mentioned a 3 watt he has. To think he could have said it was a 3,000,000 microwatt light!

As for comparing CP or MCD or fried eggs to lumen, there is also the fact that the actual shape of the reflector makes a difference too. This whole idea of using unheard of descriptors in advertising to try to make people think you have something you do not is just trying to be (get this) a Micro Milli Madoff.

JimL
November 9, 2009, 04:09 PM
I go back to my Streamlight. 75000 candle power is about 295 lumen's. So that's about .004 lumen's per 1 candle power.

The fact is that 150 lumen's is pretty good. The old standard for years was a 3 "D" Maglight at about 45 lumen's,
I realize as someone said again, that candela and lumens are apples and oranges - my OP even made the distinction. But when you figure that there isn't a whole lot of difference between the reflectors on a lot of these lights seems you have to come to _some_ sort of rule.

Your .004 rule seems to make at least partial sense for the "average light." I tried it on my 12000 MCD light and get 48 lumens. That compares pretty well with your mention of 45 for the 3D mag. As I already noted, they were close here.

JimL
November 9, 2009, 04:17 PM
Candlepower is the measurement of how bright it is at one spot (think spotlight or laser pointer).

Lumens is total light output.
As you can see, I said pretty much that in my OP. But such technicalities simply aren't helpful when the manufacturers use multiple non-standard descriptions. I think that Madmag's .004 rule, while not up to scientific scrutiny (short of a \$10,000 lab test), may be useful where the rubber hits the road (flash hits the BG) as opposed to where the pencil hits the paper.

geologist
November 9, 2009, 04:33 PM
I agree that the new LEDs have come a long way in terms of output, throw and battery life.

I went from a Surefire 6P to a cheapy NOMA 140 lumen light that runs on 3 AAAs.

TBS the flashlight under the seat of each of my trucks is an old school 3 D cell Maglight. It's hard to change a BGs attitude with a small, plastic tactical light ;)

JimL
November 9, 2009, 04:51 PM
It's hard to change a BGs attitude with a small, plastic tactical light
All the same, the scalloped bezel on the cheapie I just bought can do some severe convincing.

The barrel is an inch while the head is 1 1/2 inch. Gonna be pretty hard to knock it out of your own hand that way. I sure wouldn't want the thing laid forcefully alongside my head! You could take a guys nose clean off with this thing.

JimL
November 11, 2009, 01:24 PM
I looked up my \$25 12,000 MCD flashlight (A Nebo) on the internet. Oddly the first thing I found was a smaller, cheaper one (still Nebo), a \$16 96,000 MCD flashlight, according to the description. HUH?!

I'm even more convinced that the makers don't know what they are talking about.