Light-emitting diodes, or “LEDs,” have all but replaced conventional incandescent bulbs such as halogen and xeon. LEDs, basically semiconductors that glow, don’t have filaments to burn out, are pleasantly miserly with batteries and technical advances make them brighter and brighter every year.
There aren’t many disadvantages. LEDs can cast a softer, more diffused light that isn’t so good for route-finding, and one that’s “cooler” than regular bulbs, but most are as clean shining and as bright or brighter as the headlamps of old.
Number of Bulbs
More bulbs, like more bullets, can mean more firepower, although brightness also depends on the size, polish and focus of the bulb reflector. Most LED lamps have multiple bulbs, and most have a toggle function that lets you turn on all the bulbs at once, or select just a few for a longer, if dimmer, burn. Then again, multiple toggle settings can be gimmicky—headlamps with more than three settings can be frustrating. Many headlamps now have a blink or strobe setting, for signaling help in an emergency.
Think of batteries as gas tanks. The larger the tank, the more gas it holds and the longer the headlamp will burn. But more gas equals more weight. For example, four AA batteries will burn longer than four AAAs, but weigh more. Usually, headlamps with just one or two AAA batteries are for occasional emergency use, while models with four batteries or the larger AAs are better suited for all-around use, from route finding to cooking to reading.
Most but not all headlamps are watertight so they don’t short out when they get wet. Since getting caught out in foul weather from time to time is almost a certainty, only consider weather-resistant headlamps.
We list the distance a headlamp will cast a usable beam of light, but use this number as a rough guide only— there are no industry standards for what constitutes usable light, and everyone measures light a bit differently. A few headlamps let you focus or diffuse the beam to spotlight a distant route feature or broaden the light for close-at-hand tasks such as reading and hiking.
Again, there are no industry standards for how long a headlamp will burn on the same battery pack. One manufacturer, for instance, might measure burn time with the lamp set on its dimmest, most battery-efficient setting, while another might measure at a medium or high setting that shortens the burn time. Or, each company might even use different battery types. Nevertheless, by extrapolating the longest and shortest burn times listed in the charts, you can get a reasonable idea of what to expect from each headlamp.