Lumens.... bla bla bla ! any way to buy based on specs???

I am learning that lumens really don't tell you much, 200 seems easy to get but so many to choose from and no way to tell how good they are..

Can the RA Clicky be compared to another light that says it has the same output?
I keep buying lights and they are all rated at that 200 lumen mark but in no way the same side by side.

my go to light is my cree nf-007 with a 123 battery, bright , small and cheap.

Lumens.... bla bla bla ! any way to buy based on specs???

Click to expand...

this is probably an unhelpful post, but in short:

No.

shall I go into detail?

Budget lumens are much dimmer than flashaholic lumens.

The number is just a guideline, most accurate when comparing models from the same manufacturer, then getting less accurate as you look outward.

You perceive lumen difference in percentages, so 5 lumens looks much brighter than 1, but 200 lumens is only slightly brighter than 150.

Assuming the specs are accurate 200 lumen in one light is 200 lumen in another light...as far as output is concerned.

The difference is the beam. If those 200 lumens are concentrated in a tighter beam then it will be brighter in that beam. The lux will be greater in that tighter concentration.

So, what matters is whether you want more of a flood light or more of a spot light.

Lumen output is just the total amount of emitted light. So by itself is not a very useful measuring stick because it does not factor in the beam pattern.

Example.... A bare MCE flood light that emits 500 Lumens is going to appear very dim at 35 feet, compared to a 170 Lumen XRE with a parabolic reflector around it.

You know what some clever guy should do? Take a room and fill it with luxmeters all around, and create a 3D projection of the beam intensity at every range and angle using the numbers from the meters fed into a DAQ card. :devil:

wayfasterthanyou said:

Can the RA Clicky be compared to another light that says it has the same output?

Click to expand...

Most lights are lumen rated by the same method: How much does the LED manufacturer rate this LED at the power level being pushed through it. This is usually described as the "LED Rating". This is a theoretical value that does not take into account the 'lumen loss' caused by reflectors and optics needed to direct the light. Other lights, including HDS, are projected into a sphere, showing all this and averaging the amount of light before it gets to the sensor. This is usually described as "Out The Front/OTF".

LED ratings are easier and give bigger numbers, OTF gives a more accurate measure.
An OTF rating of 200 will be noticeably brighter than an LED rating of 200.

So in short, one could say that more expensive lights are built better and that the output can only be fully understood if one is to use the light not try to explain it.

Buying for lumen counts is the same as looking for a statistic on dating website profiles. They're probably lying and other things are more important.

ya. research and more research.

lumens is just another metric. yet one more spec out of many.

you do your homework - read the reviews, read other personal experiences, separate out the chaff from the wheat, understand the characteristics/quirks/strengths/weaknesses/etc of the light - then you buy your light. that's the only way to minimize disappointment. even after you do both, $#!* may happen.

Lumens tells you the total amount of light. A 100 watt light bulb produces a lot of light (1400 to 1600 lumens) but the light goes in all directions, half of it wasted going behind you.
A CPF member once started a thread titled something like "My SMJLED flashlight (~15 lumens) is brighter than my 100W lightbulb (~1500 lumens)" That is because the flashlight has a reflector that produces a focussed beam that goes out farther in one direction than the unfocused light of the lightbulb.

The measurement of how bright the center of the beam is is done 2 ways Lux or candlepower (cp). CPF members usually use Lux.

So you need 2 numbers:
Lumens for total light output;
Lux for how bright the hotspot is.

-----


The big blob of dim light on the left is from an MTE '900 lumens' P7 (probably 400 lumens actual).
The much brighter dot on the right is from a Terralux '50 lumens' TLE-1F bulb (probably 30 lumens actual).

So lumens does not tell you how much throw (beam distance) a light produces.

I got the TLE-1F bulb to produce such a tight beam by using a huge 4 inch reflector.


-----

There are a few ways in which lumen numbers are produced.

Small relatively poor Chinese companies simply can not afford to pay for a calibrated integrating sphere (do you know how much it costs to fly an expert over to calibrate the thing every few months? - in US $ too :sick2 So they grab a number off the LED manufacturer's spec sheet - 900 lumens for the P7, 700 lumens for the MCE, 320 lumens for the XPG, 220-260 lumens for the XRE (depends on bin). So you know you are seeing make believe when you see those numbers.

Better manufacturers calculate or measure the current to the LED, then look up what the LED should produce. This gives LED lumens. this allows us to estimate OTF (out the front) lumens. Light transmission range from 65% for a Maglite to 81% for a Fenix.

The best manufacturers actually have their lights measured either in-house or by an outside lab. Surefire, 4sevens, Arc, all the US big boys - Mag, Streamlight, UK, Pelican, Princeton Tec.

-

But is a single number that useful in telling you what you can expect in normal use?
4sevens Quark Mini AA2 is rated 180 OTF lumens on high.
Tri-force got these measurements:
Energizer L91 (E2)
187.9 1 sec
147.9 30 sec
145.5 1 min
144.2 2 min
143.0 3 min
Duracell AA alkaline
162.4 1 sec
151.5 30 sec
147.9 1 min
145.5 2 min
140.6 3 min
Yes the initial lumens is above spec with Energizer L91 (E2) lithium primaries but in normal operation after the first few minutes you are running around 140 lumens.
So use the lumen numbers, even the good ones as a guide, not as an absolute.

I know it's the most tired analogy in the world but it's kinda like a car. You don't shop for cars based solely on the numbers on the spec sheet. You take them into consideration, sure, but you don't buy one based solely on that.

Just like the beam shape is different even if the lumen rating is the same, a car can have a broad and useful power band mated perfectly to its specified transmission or it can have a narrow and jerky spike in power along its rpm curve where you'll be shifting every which when just to be able to actually use the engine.

The same way the ratings can be emitter lumens rather than honest, measured OTF lumens accounting for loss in lenses, reflectors and glass, car manufacturers often supply power ratings at the flywheel, not accounting for transmission loss.

Fuel economy can be calculated in all kinds of sneaky underhanded ways, just like battery life specs can count hours of unregulated, dim light.

There's no reasonable expectation that lights should be different from any other product - you can't buy anything else solely on specs, why lights?

There is an industry standard, ANSI/NEMA FL 1, that defines a set of tests for flashlight evaluation. In theory, any flashlight tested in accordance with FL 1 could be compared to any other flashlight tested in accordance with FL 1.

And even if you were to compare these ANSI/NEMA FL1 numbers the real life differences that you will see when comparing beamshots is going to be different depending upon whether the light has a floody beam or a thrower beam. My 110 lumens (measured OTF) Rebel 2D MagLED focused to a tight spot seems to be brighter than my 500 lumens (measured OTF on the same sphere) MagLite with SSC P7 at 25 yards or more. At 2 yards everything in front of me is lit up with the P7 and you would have a hard time finding the spot from the Rebel. Beam dispersion will cause the brightest light to seem dim at a distance compared to a collimated beam of lesser output at the same distance.

wayfasterthanyou said:

I am learning that lumens really don't tell you much, 200 seems easy to get but so many to choose from and no way to tell how good they are..

Click to expand...

There are plenty of good lights:
https://www.candlepowerforums.com/threads/279454

Quark lights are good without being insanely expensive - there are plenty of cheaper lights, but good lights are nicer to use than cheap ones.

Generally you can forget about Lumens and just buy good lights that you will be glad to own - the specs are not generally the most important aspect.

Somy Nex said:

ya. research and more research.

lumens is just another metric. yet one more spec out of many.

you do your homework - read the reviews, read other personal experiences, separate out the chaff from the wheat, understand the characteristics/quirks/strengths/weaknesses/etc of the light - then you buy your light. that's the only way to minimize disappointment. even after you do both, $#!* may happen.

Click to expand...

I might add, don't buy a light on impulse, and do what Somy said.

Geoff

PCC said:

And even if you were to compare these ANSI/NEMA FL1 numbers the real life differences that you will see when comparing beamshots is going to be different depending upon whether the light has a floody beam or a thrower beam. My 110 lumens (measured OTF) Rebel 2D MagLED focused to a tight spot seems to be brighter than my 500 lumens (measured OTF on the same sphere) MagLite with SSC P7 at 25 yards or more. At 2 yards everything in front of me is lit up with the P7 and you would have a hard time finding the spot from the Rebel. Beam dispersion will cause the brightest light to seem dim at a distance compared to a collimated beam of lesser output at the same distance.

Click to expand...

The purpose of the standard is to create a standard set of tests. ANSI FL 1 gives tests for light output, peak beam intensity, and beam distance (among other tests).

I'm not an expert in flashlights but I know a little about industry standards. I've read the FL 1 and I'm willing to bet if you grabbed 5 lights that had the same rated FL 1 values, those lights would be quite similar in output at the testing conditions required by FL 1. They may have additional setting or features that would set them apart, but at the tested conditions they should be almost the same.

Is the standard perfect? No. Is there any industry standard that couldn't use some improvements? Probably not.

Tom

I have a 285 lumen Fenix TK11 R5 and a 240 lumen Hope Vision 1 bike light - similar outputs, very very different light patterns.

IMO a truer picture is given by using lumens and lux at a specified distance. This is a bit like bhp and torque in a car rather than just bhp - it gives a better allround idea of how the light performs.

Some high bhp cars are a PITA to drive because they have no torque, some high lumen lights are annoying because the lux rating is too concentrated (a lame analagy but I'm trying...!)

wayfasterthanyou said:

I am learning that lumens really don't tell you much, 200 seems easy to get but so many to choose from and no way to tell how good they are..

Can the RA Clicky be compared to another light that says it has the same output?

Click to expand...

This might be repeating other information already posted, but whatever, I don't feel like reading the rest of the thread.

A lot of flashlight manufacturers base their lumen rating on LED manufacturer specs, but it's worth noting that those specs are usually stated as a range. So an LED might be rated by the manufacturer as capable of producing 150 to 200 lumen. Guess which end of the range flashlight manufacturers like to advertise? This is why two lights from the same manufacturer with the same lumen rating can have a noticeable difference in output.

The other thing to consider is that the upper end of the LED rating is under ideal conditions meaning no loss from optics or electronics. So even if you happen to get a genuine 200 lumen LED in your flashlight, you might only be projecting 70% (or less) out the front.

Now HDS lights like the Ra Clicky are different in that each light is individually calibrated to produce the advertised output, so if it says 170 lumen on the box, it will produce 170 lumen in your hand.

So what do you do? Is there a reliable way to compare the output of various lights based on manufacturer specs alone? Not really. However, most flashlight reviews do give actual out-the-front readings, so you can have a general idea of what the light is capable of.

My advice is to stop worrying about who has the biggest number, since any LED light rated 25 lumen or higher will be more than bright enough for most everyday tasks, and start looking at other more meaningful features like beam pattern and color, ergonomics, ruggedness, whether or not the light is programmable, etc.