Understanding Headlamp Brightness

A new standard aims to provide a more realistic idea of how much light you can expect and for how long.

The Problem

Headlamp packaging has a lot of tough-to-decipher numbers and icons, but there are two specs that really matter: lumens and run time. Most headlamps have between 25 and 500 lumens, which measure how much light is emitted (aka brightness). Run time (also referred to as burn time) is how long the light will last on a full set of batteries at a set brightness level. So when a headlamp says it can pump out 300 lumens with a run time of 100 hours, you’d be forgiven for linking those two data points and assuming you’d have 300 lumens for 100 hours. In actuality, you will only have 300 lumens for a little while after loading in a fresh set of AAAs before the power drops off dramatically.

So where does that 100-hour run time figure come from? Well, until recently, major brands used something called the moonlight protocol to calculate that number. It’s relatively simple: Turn the headlamp on at full power, and once it’s dimmer than a full moon 2 meters in front of you, stop the clock. But not only is that number abstract, for recreationistswho want to see farther out than 2 metersit’s kind of useless. 

The Solution

Here’s where the new standard comes in. PLATO, a trade organization for portable lighting manufacturers, developed the ANSI/PLATO FL 1 Standard, which Petzl, Black Diamond, Princeton Tec and others began introducing this summer. 

Along with establishing firm rules and procedures for how brands measure things like a headlamp’s lumens, beam distance, impact resistance and waterproofing, it sets the clock-stopping point for run time at 10 percent of the light’s original brightness. So, if a light starts at 300 lumens, its new run time, according to the FL 1 standard, is the amount of time it takes for the headlamp to dim to 30 lumens (which is brighter and more usable than the light of a full moon). 

That means that run time figures on headlamp packaging will start to seem a lot lower than they have in the past. (For example, the Petzl TIKKA, which used to show a run time of 60 hours at max power, now advertises just 2 hours, though it’s even more powerful with 300 lumens, instead of 200.)

For our part, at REI we’re aiming to train our staffers on the difference, so you, as a buyer, know which metric your new lamp goes by. And whenever possible, we’ll note the relevant testing standard on new product pages as well. 

Extra Credit

Still with us? Good. Then you’ll, of course, have picked up on a caveat: The arithmetic puts a headlamp with a high number of lumens at a disadvantage. Take Black Diamond’s high-powered, 500-lumen Icon. “At 10 percent, there’s still way more usable light available,” points out Black Diamond’s Lighting Director Joe Skrivan. Using the FL 1 standard’s 10-percent rule, run time would be determined by when the headlamp drained to 50 lumens—which is more than enough needed for hiking, running or even cycling at night. (Some headlamps max out at 50 lumens.) 

To standardize a minimum amount of light usable by outdoor enthusiasts specifically, both Petzl and Black Diamond are including a “Reserve” run time in addition to the FL 1 run time on headlamp packaging (you won’t see that on REI’s product pages quite yet). This new number assumes a headlamp may be usable beyond the FL 1 standard’s 10-percent rule but still improves on the moonlight protocol by essentially saying that you need to be able to see 4 meters in front of you (instead of 2 meters). So, the reserve time represents the additional time you’ll have beyond the FL 1 standard. In the case of the ACTIK CORE (which has 450 lumens), customers will see a burn time of just 2 hours, but a 3-hour reserve.

The updated figures may be confusing to customers, especially if they notice the considerable drop in run time (like in the Petzl TIKKA), so be sure to look for a clear “FL 1 Standard” marking on the packaging. And don’t forget that the diminished numbers don’t reflect a decrease in performance—they simply give users a more realistic breakdown of how much light they can expect and for how long. 

Looking to buy a new headlamp? Check out our Headlamps Gear Guide, as well as these staff and customer favorites: Black Diamond Spot325, Petzl ACTIK CORE and BioLite HeadLamp 330. All three are up-to-date with the new specs per FL 1. 

Learn More: How to Choose Headlamps

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