User Review: Petzl NAO Headlamp
Source: received for testing via the Trailspace Review Corps (sample provided by Petzl for testing and review)
The Petzl NAO is a very high tech headlamp featuring a wide range of brightness levels (15 to 355 lumens) and automatic adjustment of brightness according to ambient conditions. It is intended for use in a wide range of outdoor activities, including mountaineering, orienteering, trail running, via ferrata, rock and ice climbing, and many more. The included lithium-ion battery is rechargeable and may be mounted on the head strap (standard, and as tested) or optionally on a belt strap for extreme cold conditions. Petzl has long been known for their high performance headlamps.
- Bright focused LED, paired with lower brightness diffuse LED for reading.
- Programmable light level profiles to match the activity, from trail running to pre-dawn approaches to bivouacking (pre-programmed and customizable).
- On brightest setting, excellent for route-finding for pre-dawn approaches, running orienteering courses, or those late night descents back to the trailhead.
- On lower settings, excellent for reading when tent-bound or bivouacking.
- Automatically variable light level (Reactive mode), works well for mapreading while hiking or orienteering.
- Standard AAA Lithium and Alkaline batteries can be used in an emergency.
- Heavy with battery mounted on headstrap (especially on helmet).
- Reactive Mode should not be used while bicycling (Petzl recommendation).
- Computer needed to select or modify lighting profiles.
- Battery life is too short for long night approaches, trail runs, or orienteering, unless you stay at low light levels, and also for multiday expeditions (requires frequent recharging).
- Cannot use non-Petzl rechargeable batteries (lithium, NiCd, or NiMH rechargeables).
- Battery indicator does not work with standard alkaline or lithium batteries.
Weight: 6.75 oz /192 gm
Suggested price: $175
Warranty: Three years against any defects in materials or manufacture.
Over the years, I have used everything from candle lanterns, kerosene lanterns, and carbide headlamps through various battery-powered miner’s headlamps to the current lightweight LED headlamps to make approaches to climbs, ski tour and orienteer at night, go spelunking, and commute by bicycle. The scrap pile has also included the vaunted MiniMag lights.
This catalog of lamps has included a number of headlamps by various companies, many of which I have roundly cursed in the dark of the night when they failed me, some due to batteries or running low on carbide, and some due to failures of the lamps themselves by burned-out bulbs (with no spare available), broken wiring, or broken contact springs, or just plain too dim. Most of my Petzl lamps have done very well (in spite of the deficiencies of battery technology), including the Myo5 and Zoom.
Over the past 10 years or so, headlamp technology has made huge leaps forward in dependability and light weight (thanks to the brightness and efficiency of LEDs and improvements in batteries, both standard lithiums and rechargeable lithiums and NiMH).
For many outdoor activities, whether on the trail or in camp, having a light source that is dependable is vital. I heavily use lights for approaches, returning to the trailhead or camp after a long day, reading the map or a book while holed up in the tent. There are several requirements I have for a lamp:
- It has to have a long enough life to provide light during the full duration of the trip, including any delays.
- It has to provide an appropriate level of light during the various stages of the trip.
- It has to be light enough weight to be comfortable to wear, or for a tent light, have a convenient way to hang it.
- For map reading, the color of the light has to render all the map colors clearly (I have had the experience of a light with a yellowish or reddish tint making yellow or red markings almost invisible or in some cases producing a color shift that masked details).
- It has to be durable enough to survive the rough handling that inevitably happens during an expedition.
- It has to be easily found in the pack (none of those tiny black LED lights that hide inside a black pack!)
- For my winter, high altitude, and polar trips, it has to perform at low temperatures.
- The final question is “Do I really need a headlamp this bright, this automated, and this expensive?”
I had briefly looked at the NAO at the Outdoor Retailer Show, and dismissed it as a fancy gadget that was not likely to be truly practical. Still, being a gear freak, it did intrigue me. So when Trailspace’s Chief of Gear Reviews, Seth, told me it was available to test and review, I decided to check it out. Due to a previously assigned reviewer, (not Petzl), it arrived with several items missing, including the instruction sheet and the USB A to B cord in particular. The USB cord is needed to do the programming of the lighting profiles, as well as charging the battery.
Luckily I had such a cord, and the instruction sheet is available online, as is a huge amount of useful material. Petzl is excellent in providing detailed information on how to use their gear properly, and in this case, detailed information on how the performance parameters are determined. Like all the most recent high-powered headlamps, the list price is pretty stiff, though based on my tests, well worth it.
Step 1 was to plug the battery into one of my USB wall adapters to insure a full charge.
Step 2 was to download the Petzl OS software so that I could program the profile.
You can either load canned profiles or customize a profile for your particular usage. The supplied profiles include MultiSport, Mountaineering, Trail Running, Orienteering, Bivouacking, Caving, and Around Home, with both Reactive and Constant modes for each.
I was puzzled about the lack of a bicycling profile, until I ran across the following statement in the instruction sheet – “Do not use the lamp in Reactive Lighting mode when road biking: the lamp can dim significantly when exposed to automobile headlights.”
Reactive Lighting Mode: During my testing, I established that indeed this is the case, as well as dimming when you are going along a trail where there is a mix of dark trail or trees and very light surfaces, like dried grass (which we have at this time of year here in California) or snow, or even an oncoming hiker with a headlamp.
If you are looking around, thus moving the direction the sensor is pointing, this can sometimes be disconcerting, though I became accustomed to the changes and could anticipate when they would happen. With an oncoming car headlight, the road ahead of the bicyclist could virtually disappear suddenly. I even found on my Full Moon hike that turning a bend in the trail to face the full moon, the Reactive Mode goes to a very low light level to save battery life.
Your alternative is to run the headlamp in the Constant mode. It is easy to switch between profiles and between Reactive and Constant modes with the multifunction rotary switch. This switch also has a “Locked” position to prevent accidentally turning the lamp on in your pack. I have had dead batteries on flashlights, GPS receivers, MP3 players, and ham radios more than once due to the switch being accidentally depressed in the pack or a pocket (many devices have poor switch designs that allow accidental depression, as more than one friend has found out with PLBs and PLB-type devices).
Details of Testing:
Getting familiar with the control of the Reactive Lighting mode took a bit of experimentation. I settled on loading four modes into the headlamp’s memory that come close to activities I frequently participate in — Mountaineering, Orienteering, and Bivuoacking (which I do more often than I might like, the result of going on long expeditions and having to sit out storms), plus the “standard” Multi-Activities profile. The Multi-activities profile is described as “level 1 is for high speed activities and maximum brightness, with Level 2 for longer battery life.” In all profiles, the default “mapreading” level is 1/5 as bright as the level you were in before glancing at the map.
Battery Life (static): The first series of tests I did was largely getting familiar with the headlamp. I did some “static” battery life tests, which consisted of setting the lamp pointing at maximum brightness and covering the sensor with black tape. As expected, the battery life was short, averaging about 1h19m. Measurement of the brightness with my Sekonic 758DR meter indicated that the 355 lumen rating is correct, though I do not have the setup Petzl describes as their test setup and did not get the exact values. Later measurements of the relative levels in the profiles gave the ratios of the levels very closely.
Lamp Temp: The lamp head does get quite warm, as Petzl states in their information pages on their website. This is expected from the high output of the primary LED. I did not find the temperature uncomfortable when wearing the headlamp directly on my head or on my helmet, though the combination of headlamp and helmet is rather heavy (especially when I mounted my GoPro camera on the helmet as well).
Waterproof: Since many of the intended activities are likely to involve heavy rain or snow, as well as wet snow, not to mention the potential of accidentally dropping it in a stream or lake, I checked the waterproof qualities by immersing the lighted headlamp in a sink of water for several minutes. The NAO passed this crude test with no problems at all. Petzl’s rating on the lamp with the battery holder sealed and the power cable plugged in is IPX4 (protected against sprayed water). Petzl, by the way, strongly recommends against immersion (IPX7).
My preliminary distance tests consisted of going to one of the few parks around here that allow night entry (but be out by 10:00PM!). Barb and I took our BearIKade along with the reflectorized tape we have put on it, in case a bear tries to carry it off into the bushes, to provide a convenient way of measuring visibility distances. I also went out for a few walks around the block, during which I discovered that I could easily see our California reflectorized license plates and stop signs up to a block away.
Our area has standardized 1/8 mile blocks, so I was spotting the reflectors up to 200 meters away. Of course, this is not like seeing details that far away in the dark woods or on a mountain trail, since stop signs and reflectorized license plates are intended to be seen at long distances. During my long hikes (described later), I did find that I could spot animal eyes at long distances as well. Petzl specifies 110 meters as the visibility distance at their maximum 355 lumen setting.
In trying to get photos for this review, I mounted the NAO on my Petzl Elios helmet, along with my GoPro. Despite the brightness of the lamp, I found that the GoPro is not sensitive enough to see the illuminated area more than about 15-20 feet ahead on trails, even though I could easily see details over 100 feet up the trail. I took a number of photos with my Nikon D300s by bracing the camera on top of a hiking pole, standardized at 1 second, f/3.5, and ISO 1000 for easy comparison of different settings.
This worked quite well, as can be seen in the Mission Peak summit shot below. Except for one thing – several of the photos, taken using the viewfinder, showed noise in the photo or were unreadable due to “spurious end of file” messages (the D300s is a digital camera, hence electronic). A day after encountering this, I came across a statement in the Petzl online FAQ warning of possible interference with avalanche beacons, despite the headlamp meeting FCC standards.
Interference with Beacons: Readers of my review of the Camelbak AllClear™ UV water purifying system will recall my comments on RFI with electronic devices as more and more outdoor gear incorporates electronics. I then checked for interference with my avalanche beacons, and indeed found that close proximity to the beacons introduces a significant amount of noise. The interference can be eliminated by turning the headlamp off or reduced by moving the avy beacon away from the headlamp.
Since, even with a night SAR mission, you would hold the beacon 2-3 feet from the headlamp, I do not consider this a serious problem, but one to be kept in mind. In the case of interference with camera electronics, one would only rarely be taking photos at night depending on the NAO as a light source.
I did some further testing and found that the interference generally shows up only when shooting several images in quick succession, perhaps while the image is being written to the memory card, and only when using the camera through the viewfinder, placing the camera and headlamp in close proximity. You can check the images immediately with the camera’s preview function, of course, and re-shoot if needed.
My only caution here is to be aware of the possibility when using any electronic gear (cell phones, handheld radio transceivers, cameras, avy beacons, PLB, etc) in close proximity to the headlamp.
Lumens vs. Lux: In comparing the NAO to other headlamps I have, I found that Petzl and most other companies specify brightness in lumens, while other companies give their specification in lux. If you are not familiar with light measurement, this can be confusing.
To oversimplify a bit, lumen is a measure of total light output, while lux is a measure of light “density”. The two are related in that 1 lux is 1 lumen per square meter. Since the intensity (or think of it as the energy density) falls off as the square of the distance, the light falling on a 1 meter square white test card at 10 meters is 4 times as bright as on the same 1 meter square card at 20 meters, measured in lux. If you use a 4 square meter white card at 20 meters, the total light will be the same as the 1 square meter test card at 10 meters (you have 4 times the gathering area, so the total lumen value is the same). The problem with specifications in lux is that you need to know the distance of the target surface, which isn't always given.
The amount of light falling on an object is also dependent on the cone angle of the beam. In some older incandescent and halogen headlamps, the cone angle (often called “focus”, though there was no focusing involved) could be varied by screwing the reflector in and out. None of the current LED lamps are adjustable in that sense. The NAO has two lamps, one with a relatively narrow cone of light shaped by a fixed reflector, the other, lower power LED with a diffusion screen in front of the LED. The two lamps are used combined or singly, with variable light levels for each, as programmed with the stored profiles.
Visibility Distance: Petzl and most other manufacturers state a visibility distance. Since this is normally determined according to the European standard, this is a reasonable way to get a relative comparison. The CE (European standards organization) specification uses the distance at which the brightness of a test card illuminated by the headlamp is that produced by the full moon (on a clear night, of course, not like our typical San Francisco area foggy nights). The full moon provides a 0.25 lux illumination.
My presbyopic eyes can read the second or third level headlines on the New York Times by the light of the full moon, but not the fine print of the stories (yes, I actually tried this). Maybe you youngsters can read the fine print by the full moon, though. I do find the full moon to be adequate on most Sierra trails in the open or on glaciers and snow fields.
Constant Mode: In the Constant Mode, you switch the lighting levels by momentarily rotating the lighting knob. For some situations, you may find the Constant mode more convenient than the Reactive mode. In all profiles, the Constant Mode provides only two brightness levels, which is usually plenty. The Reactive Mode profiles provided have up to 3 levels, but you can customize both modes in a profile with up to 5 levels. I did some experimentation with customizing, but found that 3 levels was sufficient during testing.
After doing the preliminary tests, I headed out on the trail to do some short night hikes and an extensive night hike, and to do an off-trail simulation of a night orienteering run.
Brightness: One of the problems I quickly discovered was that the brightness of the NAO is way too bright for busy trails. Oncoming hikers would stop and turn their backs, cover their eyes, and otherwise just stop hiking until I was past. This was despite my aiming the headlamp downward, as recommended by Petzl to reduce the intensity of light needed, and thus extend the battery life.
Based on this, I would suggest customizing one of the profiles as a “populated trail” profile, with the brightest setting being about half the intensity of the provided profiles (or maybe even less).
Mountaineering Profile: On the extended hike, the trail was much less populated, so the Mountaineering profile worked well. The extended hike itself (shown on the map below and in the profile following) was 6.0 miles, car to car, with a gain of 2100 feet (yes, I know that the diagram shows 2220 ft, but that is because the GPSR I was using adds up the errors in elevation and does not smooth the variations out – setting the record interval from the default 2 seconds to something like 30 seconds would give a more accurate result, though the measured altitudes at each recorded point are quite accurate).
At the summit of Mission Peak, I stood on the true summit and shown the NAO over at the observation pole that most people think is the summit. I measured the distance using my Leica Distal laser tape at 195 feet (59 meters). I photographed the lit area with the camera set at 1 second, f/3.5, ISO 1000.
The night was quite clear, with a full moon. The lights of the San Francisco Bay provide a background, with San Francisco itself at the right (north) side of the photo and San Jose to the left. The image is pretty much as the eye sees it. The Petzl specification of the lit distance is just over 100 meters.
On the way up and down, there were places where it was obvious that objects up to 100 meters away were visible. I also encountered a number of animals on the trail, with the cattle’s eyes being very visible at over 100 meters away (I identified those eyes as cattle, because they tended to stare blinded by the headlamp until I walked right up to them and had to detour from side to side of the trail – the cattle themselves were black angus, so the cows were almost invisible until I was right on them – it does make one nervous to see two eyes staring back at you in the dark, since there are lion, bobcat, and coyote in Mission Peak park.
Battery Life: As I approached the gate at the parking lot at 2h39m, the NAO gave a warning double-blink, indicating the battery was running low. While putting my pack and other gear in the car, the NAO gave a second double-blink. I had extended the battery life by pointing the center of the beam about 20 feet in front of me on the trail (this causes the NAO to drop to level 2, hence longer life). I did tilt the headlamp up for the final steep, rocky 250 meters to the summit, to simulate 3rd class scramble. I am not sure what the two police cars thought about this double blinking business, though they were too busy chatting to get out of their cars and ask me about it.
You can also check the battery level by looking at the indicator LED strip on the bottom of the battery case, which requires taking the headlamp (or at least the helmet) off. However, the double-blink really grabs your attention to let you know you need to do something about the battery, making it a very useful indicator of low battery.
Map Reading: While I did not run an actual night orienteering event (none were available during the testing period), I did do some off-trail jogging with a map in hand. The lamp color is sufficiently like daylight to render the colors on the map recognizable. The automatic brightness adjustment when looking from the landscape to the map and back worked very well. This has always been a problem with older lamps, since the brightness reflecting from the map is often enough to spoil your night vision.
Battery Power: This brings me to the question of battery power, a vital concern for any headlamp, especially in the activities I pursue. Some of the climbs I have done and intend on doing require more hours than are available of daylight. Some, over glaciers or snow and ice, are best done in the early morning hours, which can mean leaving camp of the bivy site at midnight or even earlier. Thus I require sometimes 5 hours or more of dependable lighting. Years ago, this meant carrying a large number of spare batteries. Also, the approaches were (and are) often at low temperatures.
Lithium batteries (both lithium-ion and rechargeable) have helped tremendously with their longer life and cold resistance. But they do not solve everything. As mentioned above, Petzl’s battery is charged via a USB connection. The images below show the battery case opened and the connection of the wires. You can purchase extra Petzl batteries for $50-$60. This appears to be the whole pack, including the case. I have not found the battery by itself at this point. Petzl rates the battery at 300 recharge cycles.
The cable between the battery pack and the headlamp itself connects with a very solid twist-lock connector, shown at the right in the images. The battery connector wires and jack do seem to me to be a weak point, although you would be disconnecting and reconnecting very rarely. I have seen many failures of this type of connector over the years, always due to someone pulling on the wires rather than the lip on the connector. A little care in the battery replacement in the pack will avoid the problem on those few occasions when replacing the internal battery.
Even though lithium batteries, rechargeable like this one or non-rechargeables, are very good at low temperatures, they do have their limits, as I have experienced in places like Antarctica and the Alaska Range. Petzl offers a belt kit consisting of a long cord and clip so you can carry the battery inside your parka to keep it warm. Petzl has had such kits for their headlamps that were to be used in cold conditions for many years (I have one for my Myo5).
You can also replace the rechargeable battery in the case with a pair of standard AAA batteries (lithium or alkaline) as shown below. The LED indicator does not work for the non-rechargeable batteries. Petzl recommends strongly against substituting rechargeable lithium, NiCd, or NiMH batteries. For the photo, I used Energizer Ultimate Lithium AAA. The battery life is, of course, quite short, but would work in an emergency.
The Petzl NAO is an excellent choice for a wide variety of outdoor activities, providing a controllable way of matching appropriate light levels to the situation. It appears to be sufficiently rugged for heavy use in active activities like mountaineering, rock climbing, and orienteering, as well as those times when you have to spend time in a bivouac or holed up in a tent of snow cave waiting out a storm. The rather stiff price is typical of the most recent high-powered headlamps, but the performance and versatility seems well worth it.
I have some minor quibbles that led me to give the NAO a minor reduction to 4.5 stars out of 5. The big quibble is that battery life is short for a headlamp that will be used on long approaches and exits in the mountains or on longer orienteering competitions where the brightest settings are of particular advantage. Some means of recharging the battery or extra battery packs would be necessary on long expeditions or backpacking trips.
A second quibble is that the battery life is limited to about 300 recharging cycles (Petzl says that at 300 cycles, battery capacity is about 70%). Another quibble is that the weight on the head is heavy, particularly if wearing a helmet and after several hours, though no more so than other bright headlamps. The weight on your head can be reduced by using the optional belt.
Finally, did the NAO meet the 8 criteria I gave at the start? My personal answer is “yes” to all eight. Whether you, the reader can answer the eighth question in the affirmative depends on your activity and level of involvement with the activity is.
In short, I would recommend that any climber, orienteer, backpacker, or others engaged in outdoor activities involving night-time activity (or spelunkers) give serious consideration to the NAO.