Flashlights: the truth behind lumens

by Erik  

Since LEDs started powering lights we have seen a huge emphasis on something called "lumens." It is a unit of measurement that quantifies how much light is perceived by the human eye. Previously, another popular unit of measurement known as candlepower (technically known as candela) was used. This article will explore the use of lumens as a measurement of modern flashlights.

I will have to get a little technical to better explain why lumens became the replacement for candlepower. Lumen is a unit of measurement that is derived from luminous flux. Luminous flux is a weighted measurement. Meaning, it takes more things into account than just beam intensity. The use of LEDs (Light Emitting Diode) has created a much larger spectrum of light than older incandescent light bulbs.

When non-visible (infrared) and Ultra-violet light is measured along with visible light, it is called radiant flux. Luminous flux measures the entire spectrum of visible light only. Taking into account only what the human eye can see which is around 560 nanometers in wavelength. Some lights are appear "whiter" than others therefore having a higher lumen rating. It's important to understand that one light may be rated almost double the lumens over another but not actually appear twice as "bright."
LED lumen rating
Along with the color of the beam, the angle or "spill" can be different which also affects the lumen rating. A more focused (less spill) will have a higher lumen rating than less focused (more spill) light. It's also important to know that different manufacturers will measure their lights different ways. Some (like Surefire) will measure light spherically using multiple photometers which give the most honest lumen rating.

So what about a $35 weapon light that claims to have the same similar lumen ratings as the $235 light? In most cases, the low-end light is measured in candela units through a tube or cone. Using this method yields the "best" candela rating which is then converted to lumens. In such case, you actually have an apples to oranges situation which then misleads unsuspecting consumers.

If you want a quality light be it weapon mounted or handheld, you will need to spend some money. Most manufacturers of quality lights provide a lifetime warranty. I recommend lights such as the Surefire Ultra High Output LED, Streamlight TLR-1 HL, and FOURSEVENS Maelstrom

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