Rating: 4 / 5
i would classify this headlamp as a "low-end" luxeon-type headlamp. by low-end, i mean a smaller, lighter headlamp, running on AAA batts, generally lacking, or not requiring an over-the-head strap since the headlamp is also physically small and light. While much more powerful than earlier small headlamps employing only 5mm LEDs, it is still smaller and lighter than Luxeon-type headlamps running on AA batts. I would not compare this headlamp to some of the latest 1W and 3W Luxeon-type LED headlamps running on 3 or 4 AA batts. These units are larger, heavier, somewhat more expensive, and a bit more powerful, and as such should comprise a separate class of headlamps for the purposes of rating - IMHO.
I would echo all of the positive comments of the original poster/creator of this Review Thread.
The EOS provides plenty of light output on hi for rapid nighttime orienteering even over uneven terrain or on indistinct leaf covered trails. The main drawback to this mode is the very short regulated batt life - but, what can one expect from just three AAA batts. The good news is that after a mere approx. two hrs of regulated output the EOS will "auto-magically" switch to unregulated output to extend the "burn" time from the weakening batts. While this does not make batt life on the maximum/high output setting exemplary, it does make it adequate.
However, even more good news, is that, in most cases, the EOS is so powerful, that use of HI/maximum output is not necessary. Even on Medium output, the EOS produces so much light that nighttime orienteering is easily "doable". In an emergency, the EOS with fresh batts could be used on Medium setting continuously for most of the night (before the light output becomes too weak to really see any great distance) to get one out of a difficult situation should the need arise. In a pinch, even LO/minimum output can be used to slowly walk a distinct trail.
On high, it was quite easy to see blazes on trees 50' to 60' away. On medium, blazes were visible 30' away. Of course, when the batteries begin to drain and the EOS is operating in unregulated mode, then distance viewing begins to degrade. I consider 30' the minimum distance I prefer to be able to see ahead in order to rapidly traverse a trail in the dark. This gives me plenty of time, when on unfamiliar trails, to examine each of the upcoming trees for "blazes", indicating an abrupt turn/bend in the trail, even when moving relatively quickly At 5mph one is traveling ~7.3 fps, & so one has ~4seconds to spot a blaze if one can only see 30' ahead. I also feel that the beam pattern of the EOS requires this. Keep in mind that more head turning is req'd to spot/"pick out" a blaze amongst many trees as one gets closer to it. This is most of my logic behind my arbitrary 30' requirement.
When the batts are fresh, the EOS is a bit bright, even on low, for use as a task/proximity light.
Better battery life would be, perhaps, the best way to improve the EOS performance . Since, electronics already exist in the EOS to regulate the current driving LED, then for a small size/wt gain (~0.4oz for alkaline & ~0.27oz for Li) a fourth AAA batt could be used. I know that this would make the EOS a tad heavier, but for some the increased "burn" time would be welcome. This would especially have a very positive effect on the length of time the EOS operates as a constant output regulated headlamp. That is, the extra voltage provided by the fourth batt would allow the total voltage to remain high enough above the threshold req'd to operate the voltage regulation circuitry. Since Even more sophisticated electronics could allow the system to recognize low voltage, as the batts drain, and switch to a "step-up" mode of operation. The net effect of this would be to extend slightly the regulated output time, and would operate the EOS with decreasing output for a somewhat longer period of time. A slight wt. gain would again be a side-effect of the added electronics. Based upon experience, this voltage "step-up" type of circuit might increase by a couple of hours, to a few hours at most, the "burn" time.
A second improvement would be an integrated diffuser lens to facilitate use as a task/proximity light. However, for a mere ~0.2oz a Photon Microlight can be carried, making this "improvement" less compelling.
As much as I like the EOS, in actuality since the advent of the Tikka XP, a slightly better headlamp - IMHO, I would lower the rating of the EOS slightly to perhaps around 4.5 or 4.75. The Tikka XP would get somewhere about a 4.8 by my way of thinking. That said my experience with the Tikka XP, at this point in time, is somewhat limited, so this is only my initial impression of the Tikka XP. I feel that this initial impression will either be confirmed or drop.
The 4 rating is based upon it's TOO NARROW (too small a diameter) beam, forcing one to bob one's head about like a chicken to focus the beam on rocks & trees in order to spot blazes. Other than this 'crab', it's about perfect.
Link to a Post which contains additional info