Princeton Tec EOS Review


Dec 6, 2005
New York City
(this submission to be considered for the reviews sub-forum)

Reviewer's note: I received the review unit from Princeton Tec for the FCW-6 event, free of charge. Special thanks to the guys at Princeton Tec for sponsoring another great CandlePowerForums event!


(More photos, plus hi-res versions at

The EOS is one of Princeton Tec's most popular headlamps. It is a classic headlamp, having been on the market for more than five years now, but despite its classic status, it is not outdated or outdone by competitors. Princeton Tec recently upgraded their popular EOS model to the Rebel Maxbright 100 LED, which is an excellent LED by a company that practically invented power LEDs, Lumileds. It's a modern emitter, performing comparably to the EZ1000 die-based LEDs, the Cree XR-E and Seoul P4, and has allowed Princeton Tec to raise their lumen rating from the original paltry 20 lumens to a whopping 70 lumens, which, is more than bright enough for most users' needs. Thankfully, the EOS has 3 output levels, so that you do not blind yourself and everyone around you when less light is necessary.

What separates the EOS from the rest of the pack in the crowded consumer headlamp sector is that the EOS is one of the only headlamps that run fully regulated, meaning that there are electronics that maintain a constant level of brightness until the batteries can no longer sustain that output. Princeton Tec smartly designed the EOS to drop into direct-drive after the regulation can no longer be sustained, which prevents the user from being unexpectedly left in the dark without a light.

The packaging claims that this headlamp is made in the USA, which is a refreshing change of pace, but would be naught if the quality and performance of the headlamp itself were terrible. Thankfully, this is not the case. The EOS is stunning.

Before writing this review, I have taken the EOS on several camping, backpacking, and hiking trips, using it extensively for camp chores, night hikes, and around the house. It has greatly exceeded my expectations and is looking like an extremely strong contender for my upcoming 5-month long thru-hike. Since the EOS's target market is outdoorsmen, I will evaluate the EOS from that perspective.

The EOS is molded from some high-tech polymer, the kind that is shatter- and impact-resistant, so it is both light and very strong. When I pack my EOS for a trip I do not bother to put it in a case, I just chuck it in my pack. At 105 grams (3.7 oz) loaded with batteries it is not quite as airweight as I would prefer but it is still fairly light and hardly heavy enough to ever consider leaving it behind.

The EOS is water-resistant, and Princeton Tec rates it as being waterproof to 1 meter. This is more than sufficient for their target audience, hikers and backpackers, and it survived several heavy rains unprotected. I also used it in the shower once during a power outage, with no indications of water ingress or damage.

This headlamp, like many others that are offered alongside it in retail, runs on 3 AAA batteries. This is not my preference, but appears to be the industry standard for headlamps in this price range. Given the EOS's extremely good performance on said batteries, I have reversed my initial stance on the 3 x AAA form-factor — I no longer believe that using so many AAA batteries is necessarily an indicator of poor performance, although it seems to me that this headlamp is an exception to the norm. Princeton Tec says that lithium primary AAA batteries are okay to use in this headlamp, which should make it lighter and run for up to six times longer on high, by the company's measurements. (Low is virtually unchanged with lithium primaries, only gaining 10% more runtime.)

To change the batteries in the EOS, one must simply unscrew a single thumbscrew (aided by the plastic band adjuster), swap three batteries, and screw the thumbscrew back on. The door and its hinge both appear very sturdy, with the thumbscrew having a metal nut to screw into, so this light is designed to last. Also notable is the gasket on the door, which prevents water ingress into the battery compartment. The visible internals of this headlamp are quite remarkable, in fact, oozing of quality that is very surprising at its fairly low retail price ($45 MSRP, although it can be found for a good deal less).

Princeton Tec rates the EOS as running for 1 hour regulated on the brightest mode, (70 lumens), which seems like an understatement from my experience, although I do not have the equipment to measure to be certain. Runtimes increase significantly with lower output settings, getting 10 hours at the medium setting and 50 hours on the lowest setting. Based on my experience using the headlamp with Duracell alkalines, I have no reason to believe that these runtimes are exaggerated.

The output levels are well-spaced, although I would have preferred even greater differentiation between the three levels. I consider the lowest output to be more than enough for night hiking, which means the low mode isn't quite low enough for my tastes for reading in bed, for example. However, the spacing of the output levels isn't enough of a concern to dampen my high opinions of this headlamp.

Switching the light through the modes is easy. Starting from 'off,' clicking the single button on the top (which is stiff rubber and also well-sealed) will cycle the light from high, to medium, to low, to signal (steady blink), to off. Once the headlamp has been on for a few seconds, clicking the button again will not cycle through modes, instead turning the headlamp off. My preferences dictate that the light start on low first, but again it is not a deal breaker and can indeed be handy — for instance, if you are disturbed at night by a loud noise and wish to look around, a single click will light up your entire campsite with ease. The button itself has excellent feedback with a satisfying click and does not feel the least bit flimsy.

In my uses of the EOS, I was continually impressed by the excellent beam quality and the well-balanced beam, which offers the wearer a good mix of both flood and throw, negating the need to carry a flashlight when one needs to illuminate objects in the distance. (That's weight saved, right there!) The EOS's beam is smooth and without artifacts or rings, making it a joy to use at all distances, although it may not be the ideal choice for reading in bed due to the throwy quality of the beam. A floody beam is preferable for close up work, and for those who must read with their headlamps after a long day's hike, the Remix or Remix Pro might be a preferable alternative. Although color tint of the LED may vary across individual lights, my sample (of two) appear very similar and have a fairly neutral color that appears to be near 5000K.

The elastic band provided is seemingly nothing special but it is comfortable to wear for extended periods of time and so does its job just fine. It is fairly attractive to look at and advertises the fact that you are using a Princeton Tec so that you and your friends do not forget what kind of headlamp you are wearing.

The hinge that allows you to tilt the headlamp is, sadly the one thing that I find somewhat unsatisfactory on an otherwise incredible light. It performs its function just fine for hiking and walking but one must take care not to do jumping jacks or other excessively vertical movements because it will cause the headlamp to flop downwards. However, while doing normal backpacker stuff, I have never had to readjust the headlamp, so it is likely an issue that most users will never encounter. I am also concerned that it will wear out over time as it is plastic-on-plastic and reliant on the flex and friction of the contact but during my four month evaluation there was no change or noticeable wear. Nearly all headlamps with an adjustable tilt rely on friction to prevent the light from pivoting excessively but in the EOS's case its heavy body may make it more susceptible to pivoting. I believe that if it should become a problem in the field, a small piece of duct tape on the wear area will rectify the situation. In any case, this concern is mitigated by carrying duct tape in your pack (which you should always carry for field repairs anyway).

Overall I am extremely happy with this headlamp and will probably buy another one as a loaner when some gear-less friend wishes to go backpacking with me. I am impressed with its performance, low cost and high value, and excellent build quality.

Highly recommended.


Jul 8, 2010
The Lone Star State
Love the EOS but I've hopped onto the ZL train. :nana:

I find the smaller size of the ZL and the moonlight mode is more useful and a lot more comfortable outside the house and inside the house.

Still, there's always a place in my heart for the PT EOS and I still recommend it to everyone I know.


Flashlight Enthusiast
Dec 22, 2004
Nice review Carrot.

Great light; I've gifted a few of these to friends who hike and they have all been working really well. Everyone has been happy with theirs.



Newly Enlightened
Oct 2, 2010
Great review. I have the bike version (the same except it comes with a handlebar mount/velcro strap/headband) and I love it.


Flashlight Enthusiast
Oct 19, 2009
Nice review. Since I just bought one I'll make a few comments as well. I agree with everything above. The beam while artifact free and nice looking is a bit like looking through a tunnel (hard drop-off to the edges) and could use a bit more spill for your feet. I added a piece of tape over the lens and it fixed that issue for me.

The only real change I'd make to this headlamp would be a lower low as was mentioned above. It seems to me the low must be around 25 lumens...5 would be better.

It's one of the best deals out there however all things considered.