What the heck is a lumen...and why should I care?

Class 103

What the heck is a lumen...and why should I care?


In the film Crocodile Dundee, a mugger threatens Mick Dundee with a switchblade. Mick seems amused and then delivers his famous line “That’s not a knife. [pulls out a large bowie knife]. That’s a knife.” Much like Mick was amused by the switchblade, we’re amused by some of the lumens we’re seeing reported from "tactical" lights on the market.

While a knife is a knife, all knives are not created equal. The same can be said of lights. Lights, like knives, vary in size, quality, craftsmanship, etc. There are different kinds of knives and different kind of lumens. In lighting, this causes a problem because some light manufacturers "purposely" don't distinguish what kind of lumens they're stating.

A light's intensity is measured in lumens. More lumens means more light, which typically makes a light more attractive and valuable to end users. If light manufacturers manipulate lumens for their own advantage, it makes it hard for customers to accurately compare two lights and can cause some customers to get ripped off. We don't want you getting ripped off so here's a quick lesson on lumens.




"This is a knife."

There are two ways to express / quantify lumens:



  1. What THEORETICALLY SHOULD come out of the lighting components (Emitter Lumens; AKA Bulb Lumen)
  2. What ACTUALLY comes out of the light (Torch lumens; AKA Out the Front Lumens)

Here's the best and simplest way we can explain Torch vs. Emitter lumens:

Emitter lumens are NOT what you get when you turn on the light.

  • They are impacted by losses in lenses, reflectors, and other optics.
  • Lower quality lights with poor craftsmanship, substandard finishes and materials will waste a lot of light before it gets out of the device, and can lose up to 60% of the Emitter Lumens, before light makes it out to the real world.

Torch Lumens tell the truth about "what comes out of the device".

  • This number will be the real world number, and even in the best devices, it can be around 20% lower than Emitter Lumens.

Why Does This Matter So Much (When Comparing Lights)?

Failure to disclose the specific type of lumens measured can lead to inaccurate comparisons.

Using Emitter Lumens instead of Torch Lumens, will make a cheaper flashlight look much better than it really is.

Example: FoxFury’s 220 Torch (OTF) lumen Rook MD1 Flashlights is actually brighter than a 280 Emitter (Bulb) Lumen flashlight.


If you're unsure about what type of lumens a light manufacturer uses in its measurements, then ask.

If a flashlight seems like it's too good to be true, then it probably is.

In other words, don't expect BMW performance at a Yugo price.



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FoxFury Lighting Solutions designs, manufactures and markets portable LED headlamps, flashlights, shield lights, scene lights and area lights. Our application-specific LED lights are used in firefighting, police, military, industrial safety, hazardous area, filming, photography and more. FoxFury uses the newest LED technology from top manufacturers like CREE, OSRAM and Nichia. White light along with multi-color and wavelength-specific forensic light sources (from UV to IR) are available. Our compact LED lighting tools are tough, waterproof and impact resistant. FoxFury also offers fire resistant and intrinsically safe / explosion proof lights. FoxFury is best known for its wide angle LED headlamps and Nomad portable scene lights.

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