A headlamp is a standard part of every climber's gear; I don't think I know a single one who doesn't keep a headlamp in their pack. I have a number of older ones laying around in the basement, some dating back at least 20 years, and they still work. The questions is, are they worth replacing with one of the new super-duper headlamps like the Petzl NAO?
Petzl has been making headlamps, what seems like forever. The last couple of generations has seen them move away from the incandescent bulb versions to LED, with a brief stop at one model that had both! Most of the advances in headlamp technology, after LED's, seems to mostly revolve around ways to improve battery life. While Petzl has addressed this, they have done it as a part of creating a new technology called Reactive Lighting. This new technology allows the NAO to change its output by measuring the surrounding ambient light, and adjusting its output accordingly. Here's some examples of how it works:
1) if you are in a pitch black night and there are no close objects, the NAO beam becomes focused and its light intensity increases;
2) If you look down at your map to check your location, light is reflected back to the NAO's sensor and the intensity is reduced and the beam becomes wider and more diffuse;
3) If you are icing on a trail, the beam automatically adjusts to a medium intensity and a moderately wide beam.
When I say automatically, I really do mean that. You don't have to do any of this stuff manually. It is very cool to see how the sensor adjusts the beam in real time. And if you're hiking with a partner, if the two of you look at each other, as you often do, the NAO automatically dims do you aren't totally blinded.
All of this automatic adjustment provides you with better battery life. According to Petzl the battery "provides 4 hrs. 40 min. of use in high Reactive mode and 8 hrs. in low Reactive; offers 1 hr. 20 mins. of use in high Constant mode and 8 hrs. in low Constant". In my testing the NAO came in pretty close to these values. The proprietary lithium battery can also be replaced with 2 AAA batteries in a pinch, and that's pretty cool. While the battery is a 18650 Li-Ion cell, it is connected with the wire and plug. Unfortunately this prevents you from using the readily available, and cheaper, 18650!
The NAO can be charged from a power adaptor (optional at extra cost) or the USB port on your computer. While the power adaptor charges quicker, Petzl provides a free downloadable utility for both Mac & PC that you can use to "program" the the battery life of the headlamp or the lighting level (maximum or economic mode) according to your needs. If you are interested I suggest that you download the manual and check it out.
The strap is reasonably easy to fit hand adjust and I had no problems getting it to fit on my head, over a knit cap or on my climbing helmet. However I couldn't figure out how to get it on my Giro mountain bike helmet! The on/off switch can also be locked to keep it from accidentally turning on while in your backpack.
The NAO is definitely a cool toy and from what I see of the personal headlamp market, Petzl is currently leading the way. It has a lot of great features and I'm sure it be popular. The only downside IMO is the price. At $175 list, the NAO is at the top end of the market and thus is quite an investment. That said, it's a very nice headlamp and I think it deserves the 5 thumbs up rating!
Brightness: 2 LED's shine light up to 108m and output 355 lumens on high Reactive mode and 55m and 98 lumens in low Reactive mode.
Battery Life: Battery provides 4 hrs. 40 min. of use in high Reactive mode and 8 hrs. in low Reactive; offers 1 hr. 20 mins. of use in high Constant mode and 8 hrs. in low Constant.
Charging: Single Lithium-ion polymer 2,300 mAh battery can be recharged up to 300 times, making the battery life equivalent to that of hundreds of alkaline batteries.