The following are the main variables that differentiate headlamps:
|Specifications||Reported In||What It Means|
|Light output (brightness)||Lumens||At its source, how intensely the light glows.|
|Beam distance||Meters||On nearby surfaces, how far the light actually goes.|
|Hours||How long (at its lowest setting) a light projects "usable light."|
|Weight||Ounces or grams||Many range between 3 and 6 oz.; high-intensity models weigh more.|
|Size||Inches or centimeters||Top straps and external battery packs accommodate more power but add bulk.|
If you're in a hurry, here's a crash course in headlamp selection:
The following sections provide details on headlamp specifications.
Lumens are a unit of measure that gauges the total quantity of light emitted in all directions by a light source. Watts, traditionally featured on the packaging of conventional household light bulbs, are a measure of how much energy a light uses. Typically, though, a light with a high lumens count will consume energy at a higher rate than a light with a lower lumens number.
So, the higher the lumens, the brighter the light? In most cases, yes—but not necessarily. Lumens are measured in a spherical device, capturing light emitted in all directions by the source. Yet how well a headlamp maker focuses and directs that light (via lenses and reflectors) can impact how those lumens are utilized. If, for instance, a headlamp uses a translucent casing, some lumens will escape through that casing and not contribute to the overall strength of the beam.
Manufacturers are rarely shy about touting lumens on their packaging. A lumens count is useful to know, but it is just one of several factors that tell a headlamp's complete story.
Lumens tell you how brightly a headlamp glows (at its source), but not how far it goes (to a surface you want illuminated). This is a headlamp's fundamental purpose—to channel light to a target area.
Headlamps are tested to determine how far (in meters) they can project usable light, defined as the light cast by a full moon on a clear night. In the lighting industry this is known as the "moonlight standard," which is especially relevant to outdoor adventurers.
The light of a full moon is considered sufficient light for a person to navigate cautiously but safely through outdoor terrain.
To meet that standard, a light meter must be placed on a surface and register a minimum reading of 0.25 lux (the light intensity of a full moon). Lux is a measure of light where it falls on a surface that it illuminates.
To envision how beam distance is tested, imagine a headlamp with fresh batteries attached to a fixed position. It is switched on, placed on its highest mode, and a light meter (technically known as a lux meter) is moved further and further until the meter, measuring the center of the headlamp's beam, registers 0.25 lux. That is a headlamp's maximum beam distance (which slowly grows progressively shorter as batteries are drained).
While each manufacturer uses the same test for beam distance, they may display the results a bit differently.
Here is where headlamp makers part company with the ANSI/NEMA test standard. That standard declares batteries reach an exhausted state when a light can produce only 10% of its original light output (when batteries were fresh). This is usually determined with a measuring sphere.
That would leave a number of high-powered headlamps with a lot of energy still in the tank—still possessing enough battery power to project usable light. A high-intensity beacon such as the Petzl NAO (rated at 355 lumens) would still have a very serviceable 35 lumens of light available at 10% of original output.
Since most outdoor adventurers can function safely in an emergency mode with good moonlight, headlamp makers calculate run time until lights can no longer produce usable light (the light of a full moon) at 2 meters.
Why 2 meters (6'6")? The average American height is about 5'9" (male) and 5'4" (female). Thus headlamp makers consider a headlamp serviceable if it can project 0.25 lux, the equivalent of a full moon's light, on the terrain in front of an on-the-move adventurer in the dark. It's a legitimate calculation that REI's Quality Assurance Lab endorses.
Look for a clock icon plus a number of hours (usually shown in abbreviated form, such as 50h). If just one number is shown, this is the measurement of the light's lowest (most energy-efficient) setting for continuous light. Some brands show run times of all modes (low, high and in-between). The blinking strobe mode is a headlamp's most energy-efficient mode, followed by low.
Most headlamps, with batteries included, weigh less than 7 ounces and are of similar size.
You won't notice substantial differences in headlamp size and weight until you start examining some very high-powered models. Some have top straps and external battery packs that add bulk. Such models are intended for specific needs (e.g., climbing) rather than routine adventures.
Most packaging displays headlamp weight in grams. Below are some random conversion figures to speed up mental calculations for non-metric minds.
You may not know your preferences on all of the following secondary topics right now. Don't fret. Such understanding is usually gained only after much fiddling in the field and comparing headlamp notes with your companions.
Most headlamps offer at least a high and low mode. Others may offer 3 or more modes, alternately called "brightness levels." Here's a breakdown, moving from the most energy-efficient mode to the least-efficient:
Many headlamps offer a red-light mode. Red light does not cause our eye's pupils to shrink the way white light can, so it's good for viewing the night sky.
Some headlamps offer a fixed beams; others are adjustable. Two fixed widths are:
Adjustable beams are more versatile. Manufacturers have different ways of indicating this feature on their packaging, often showing both wide and narrow beams.
A strong center beam is not necessarily indicative of a great headlamp. A laser beam, for example, projects an incredibly powerful beam of light but is so narrowly focused that it illuminates virtually nothing.
Some headlamps may not throw light the longest distance, yet they do a nice job of filling its beam with an even density of light, so a larger surface area of an illuminated object will be brighter overall across a wider area.
This is often a desirable attribute. Some lights that cast long beam distances project a very strong center axis of light—so strong that it creates an extra-bright center spot during up-close viewing, such as reading a map. During extended viewing, a bright center spot can create a glare that becomes annoying.
Headlamp packaging does not convey beam quality information, primarily because it's tough to verify through any objective measurement. Some manufacturers individually test for "beam fill" by evaluating the density and evenness of a beam's strength as it falls on a broad 9-point grid (3 points high, 3 wide). If a headlamp claims enhanced beam quality, you'll probably find it mentioned only in its product description.
Do not use lithium batteries in a headlamp unless manufacturer instructions specifically state that a particular model can accommodate lithium cells. The high nominal voltage produced by lithium batteries could damage or ruin a light's circuitry not equipped to handle such power.
Headlamps designed to work with lithium batteries are a good choice for cold-weather usage, since lithium batteries outperform alkaline batteries in cold conditions.
Rechargeable nickel metal hydride (NiMH) batteries also work well with headlamps and perform well in cold conditions. Read more about battery choices in the REI Expert Advice article, Batteries: How to Choose.
Tip: Rechargeable batteries tend to lose power when sitting idle, so it's smart to carry alkalines (excellent at holding their charge) as backups.
Rather than gradually dimming as batteries drain, regulated headlamps offer a steady brightness level throughout the life of the batteries. This is a positive—and deservedly popular—feature.
The downside: When batteries are exhausted, the light of a regulated headlamp can go dark abruptly. This may leave you scrambling to replace batteries in the dark. A dimming light on an unregulated headlamp gives you early warning that batteries are nearing the end of their usefulness.
Both approaches have advantages and trade-offs. Neither is considered superior.
Headlamps today almost exclusively use LEDs (a type of semiconductor) as their light source. Their advantages include:
Beware of buzzwords you might see on some packaging. Some manufacturers claim their LEDs are "superbright," "ultrabright," "TriplePower" or some similar form of megaspeak. Don't be impressed. Such terms are pure hype, not industry-recognized technical classifications.
LEDs come in various sizes (based on their diameter—1mm, 3mm, 5mm and larger), and larger usually means brighter. Some do fall in a legitimate category known as high-output LEDs, based on wattage (their ability to draw more energy). Expect bright output by any lamps that feature 1-watt or 3-watt LEDs.
LEDs used in headlamps are "tuned" to produce a white light, but be aware that most LEDs tend to have a faint blue cast to their light. This boosts their energy efficiency, since turquoise offers the most desirable wattage-to-lumen ratio. The most energy-efficient color of all? Red.
In late 2009, with input from more than a dozen manufacturers and other companies involved in the lighting industry (including REI), the National Electronic Manufacturers Association (NEMA) published ANSI/NEMA FL 1-2009, Flashlight Basic Performance Standard. ANSI is the American National Standards Institute, a private, nonprofit organization that oversees voluntary consensus product standards in the United States.
The dual goals of the standard:
Compliance with the standard is voluntary and, as mentioned earlier, headlamp-makers disagree with majority opinion when it comes to determining run time (preferring to apply the moonlight standard to headlamps). In all other areas, however, headlamp-makers conform to the test methods laid out in the ANSI/NEMA standard.
Of all the factors discussed in this article, which matter most? Brightness (light output) is high on everyone's list, but beam distance and run time also factor into the total picture of a headlamp's performance potential.
The nature of your outdoor activities will also play a role in your decision. Here are some basic guidelines:
|Activity||Key Headlamp Priorities|
|Hiking/backpacking||Weight, run time, beam distance, multiple modes|
|Climbing||Weight, high-intensity beam, beam distance|
|Cycling||High-intensity beam, beam distance, run time|
|Paddling||Water resistance, high-intensity beam|
|Snow camping||Water resistance, run time|
|Travel, home emergency kits||Size, run time, flood (wide) beam for general usage|
By T.D. Wood
Read Author Bio
Last updated: 02/18/2014
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