Lumens Matter, But They Don’t

November 4, 2015  
|  5 Comments
Categories: Learnin'

There is a range of opinions on the subject of both handheld lights and WMLs. Today we’ll walk through lights, lumens, and cognitive dissonance. 

(Grunts: Cognitive Dissonance)

In front of me I have two different weapon lights. The power sources are exactly the same. One of them is 220 lumens and the other is a hair over 1k lumens. Which one can illuminate targets farther in the dark? Easy question, right?

Lumens Matter. But they don't.

The subject of lumens, the amount of light emitted by a given source, is often contentious. though I’m currently a member of the quasi-cultish ‘All the Lumens’ movement, I admit to having toed a different line on a battlefield over this subject in the past. “XYZ lumens are too much” or “ABC lumens are worthless.”

Weapon Mounted Flashlight.

We tend to focus on the raw number of lumens more than anything else about a flashlight. If you get a new light, it’s one of the first questions people ask. Why? Because it’s a quantitative measure that’s become the industry standard. Look up a flashlight, and there it is (usually front and center if it’s a relatively high number, and small and in the back if it’s low). It’s stupidly easy.

Understand that lumens are going to be measured in the best possible circumstances. At peak voltage with full-charge batteries (actually more than likely hooked into a regulated DC source) at a distance, which will record the maximum number, your light undoubtedly won’t be as bright all the time as the advertised lumens. This really isn’t a big deal, and it’s the opposite of how the waistline is measured in your jeans from Old Navy.

And we could get into watts, lux, tint, foot candles, artifacts, and all kinds of nerdery that will give engineers and flashlight geeks massive erections but put everyone else to sleep–so we won’t. Here are some links if you want to dive in more:

Flood vs. Throw

Throw, flood, hotspot, and spill matters a helluva lot more than just raw lumens.

A comparative look at lumens - flood and throw.

Furthermore, each of those attributes has to work toward your intended purpose.

Like I said, lumens are easy numbers to spout off. Defining the others can be a lot harder. People tend to use qualitative terms like “decent flood” or “medium hotspot”. These are completely subjective terms. While manufacturers have the ability to give you this data, it will probably be worthless for most people.

A qualitative look at lumens - flood and throw.

Here’s an example:

“75 degree spill angle with 3,500 center lux at 1m, spot angle 30 degrees.”

If you troll around flashlight forums, there are people who conduct testing like this as well.

I used to be a shit-talker about ‘too many lumens’. I made condescending remarks to people with WMLs I considered too bright. And I was wrong.

“You planning on spotlighting deer with that?”

“Yeah, that will definitely make up for poor tactics.”

You could chalk this up to me being too old, or too old school. A decade and a half ago the best WMLs rocked 120 lumens for a whopping 20 minutes. And we were glad for it. Now it’s not impossible to run 10x that in terms of raw lumens. Light usage outside of a structure was also a huge no-no. But that really isn’t the reason, at least not entirely.

Demonstrating flood and throw.

I’d seen and used lights that had so much hotspot they washed out red dot sights at closer ranges. Imagine putting your light on a limited-probability target, taking quick but careful aim, and….. red dot gone. Zip. Zero. In more than one instance, a red dot got turned all the way up, so it was a blooming mess in the dark, and the dot still wasn’t visible with the light running. There are multiple ways this issue can be fixed. First, you can simply reduce the lumens. The same reflector and lens + fewer lumens = a hot spot that isn’t as bright. Secondly, a diffuser of some kind could be used to reduce the strength of the hotspot and increase spill. A brighter RDS might do it, and you could even play Audie Murphy with irons. Or, you could just go with a different reflector and lens setup.


We work pretty hard on this stuff. Do us a solid if you’re getting anything out of our writing!


Instead of giving it full consideration, I went with the ‘too many lumens’ answer. It was an easy button, and though it solved that specific problem, it also decreased the abilities of the WML in other areas (namely in flood and spill). Though any of the other options would have worked, I ended up giving myself an unneeded and unwanted handicap. And it took too long to figure this out.

A qualitative look at lumens - flood and throw.

A Tale of Two Lights

Back to that original question. Which light could spot targets at a longer distance in the dark? In this instance, they’re the same.

The 220-lumen light has a very tight hotspot with a long throw, and the 1k+ lumen light is entirely flood. If you use both in a room, the 220-lumen light will actually wash out the red dot more and illuminate through spill less. That 1k+ light? No washout and a ton of light to move around with. Despite having no discernible hotspot, it can still pierce and penetrate far into dark corners simply through the raw power it puts out.

You need enough lumens, and you probably can’t have too many lumens–but you absolutely can have them allocated incorrectly.

Don’t get sucked in. Think about what you’re using the light for. Go out and actually train with it. Admit when you’re wrong. Then try some more lights.

-DFM

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Dave Merrill

Dave Merrill

About the Author

About the Author: A combat veteran of the United States Marine Corps, Dave "Mad Duo Merrill" is a former urban warfare and foreign weapons instructor for Coalition fighting men. An occasional competitive shooter, he has a strange Kalashnikov fetish the rest of the minions try to ignore. Merrill, who has superb taste in hats, has been published in a number of places, the most awesome of which is, of course, here at Breach-Bang-Clear. He loves tacos, is kind of a dick and married way, way above his pay grade. You can contact him at Merrill(at)BreachBangClear.com and follow him on Instagram here (@dave_fm).

5 Comments

  1. TIMUR

    Amen. I run a Surefire diffuser (sadly discontinued these days) or some scotch tape on all of my weapon lights.

    • TIMUR

      —correction….surefire is making diffusers again

  2. Dann in Ohio

    Great points! I just taught a low-light pistol course last night… and your discussion also highlights why I sometimes use different lights for different situations… the light that works best in the house with mostly white or off-white walls within a few yards may not be the best light for out back in the field or around the barns or in a large warehouse…Dann in Ohio

  3. Marc

    Out of curiosity, which lights were used in the pic above showing flood and hot spots lined up side by side?

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