Lighting is one of the most overlooked categories of the backcountry kit. All functioning flashlights and headlamps produce light, and in most nighttime or low-light circumstances, any amount of light is usually good enough. But lets not forget the fact that roughly one-third of our time spent on any given backpack hunt is in the dark. Spur of the moment nighttime camp relocations, water filling trips, field dressing, pack outs, etc. are all times where quality lighting is heavily relied on- some of which require more lumen output, some of which require less. The bottom line is that proper lighting allows us to get work done safely and efficiently.
The classic drawback to using high-output mobile light sources on longer trips where weight matters is the issue of carrying extra batteries, or the fear of a rechargeable battery losing power at the most inopportune time. Variable output lamps help conserve energy, although it’s hard to predict just how much. Unless, of course, you are able to customize it to the exact intensity and duration settings necessary for a given hunt. This may sound like an outlandish idea, but with select Petzl headlamps it’s entirely possible and actually quite simple.
Petzl OS Lighting Software
One of the main reasons we chose to offer the Petzl NAO and RXP headlamps in the KUIU Gear Shop is for the ability for the user to fine tune the settings using Petzl’s free OS software. By customizing the headlamp settings, one can fine tune the balance between battery duration and lumen output depending on the hunt.
Once you have a Petzl NAO, Tikka R+, or Tikka RXP, you can download the Free Petzl OS software from there website. The link is here in case you are eager to visit the page now. After the download is finished, the program will request that you connect your headlamp to the computer via the included USB cord. At this point, you will come to the page seen in the screen shot above.
Reactive vs. Constant Lighting
Displayed above in the previous screenshot are the default settings for the Petzl NAO. At the top under Active Profiles, you’ll see two operation categories side by side: Reactive and Constant.
To clarify, Reactive Lighting is when the lamp senses the distance at which the user is looking. While looking at close up objects or the ground, the lamp lowers the lumen output and uses a flood beam. Once the user looks up at a distant object, the lamp immediately increases its lumen output and throws a narrower long distance beam.
Constant lighting is pretty self-explanatory: a constant beam is cast no matter what distance the user is looking. To change lumen output and/or beam focus, the user must toggle through settings on the headlamp.
Reactive Lighting comes in most handy for situations like blood trailing or traversing rough country at night when you’re constantly looking down and ahead at different distances. Times where the Reactive feature becomes less desirable is around camp or in foggy/snowy conditions. Friends don’t seem to appreciate a 350+ lumen blast in the face each time you look up to talk to them, and fog has a way of reflecting a lot of the high output light back into your eyes. Luckily, switching back and forth between Reactive and Constant lighting can be done in the field.
Customizations
For extended backpack hunts, the most important customizations that the OS software provides are battery life and number of different stored output settings. Below you’ll notice that the default (out of the package) Reactive and Constant settings only offer a max battery life of 8 hours at 98 lumens. 8 hours may seem like quite a while, but that’s only an average of just over 1.5 hours per night on a 5 night hunt. Furthermore, 98 lumens is overkill for general camp use and even on the high side for night hiking in mellow terrain.
In order to make the settings more user friendly for our intended purposes, we want to dim down the light on the lowest setting to extend the battery life, and also adjust the higher intensity settings for specific scenarios. By clicking “Create New Profile”, you are able to program all of your own settings within both the Reactive and Constant Lighting categories. Below is a new screen shot displaying the custom settings I’ve chosen.
As you can see there are now four different settings in the Reactive category, and three under constant. Take a look at Reactive level 4 highlighted in the photo above. The + and – signs next to the battery life are what’s used to adjust the brightness and battery life of each level. If I wanted to add a fifth custom level I could, but four seems to provide plenty of options. Also, notice how the battery life of each level increases in a (somewhat) 4, 8, 16, 32 pattern. This is by design in order to easily memorize the life of each setting while in the field. The same can be done over on the Constant Lighting side. Below is a quick explanation on the levels I chose.
Level 1, 4:40 @ 355 Lumens: Best reserved for looking for a downed animal, navigating treacherous routes, etc. This is not a setting that should be used very often.
Level 2, 8:00 @ 98 Lumens: Good for general active use, field dressing, setting up camp, etc. Still, this setting should be used wisely on a long hunt.
Level 3, 16:00 @ 26 Lumens: Should be the most frequently used setting while hiking on a trail, cooking meals, getting dressed, etc. 26 lumens is typically plenty of light for these purposes.
Level 4, 31:00 @ 9 Lumens: Best to use for extended low activity periods, reading, or down time at camp. This setting still provides plenty of light for eating, cooking, organizing a pack, etc. on hunts where battery life is critical.
Additional Advanced Settings
The OS software offers some additional settings to further refine the performance of their lamps. These setting are found by clicking “Expert Setting” on the main setting profile page. The expert settings allow the user to fine tune parameters such as wide and narrow angle beam power percentages, and most notably, reading beam threshold. This adjustment dictates the focus of the beam while looking at close up objects such as maps, notebooks, or GPS units. Furthermore, battery life settings can be tuned to very specific times within expert settings- although your really just splitting hairs at this point as far as hunting purposes go.

The reading threshold setting seen upper-right is a quality tool. Adjusting the reading beam coverage does not affect battery life.
Lastly, Expert Settings is where you will find the toggles which allow the customization of how settings are changed during use. This is located under the “Other Parameters” tab.
While there are some additional specifics to this software not mentioned above, this should provide a close enough look into Petzl OS for readers to decide whether or not its a tool worth using this season. For more information on the headlamps that are compatible with the program, please follow the links below.
Best of luck if you choose to pursue these tips, and thanks for reading.
-Todd Harney