Essential Gear K2 Focus headlamp
Test Series by Kurt Papke
Backpacking background: mostly in Minnesota - I have hiked all of the
Hiking Trail and Border Route.
This last year included hiking in Michigan, Wisconsin, Utah, Colorado,
south and North Dakota and Oregon. My preferred/typical backpack
trip is one week, mostly in the
seasons, but I started doing more winter camping this year. I
always carry several lights with me when backpacking, including a
|| Kurt Papke
|| 6' 4" (193 cm)
|| 220 lbs (100 kg)
|| kwpapke at gmail dot com
|City, State, Country:
|| Minneapolis, Minnesota USA
The Essential Gear K2 Focus headlamp (hereafter referred to as the
"K2") is a head-mounted LED lamp. It is distinctive from many LED
backpacker headlamps in several respects:
- It is powered by AA batteries instead of the more common AAA
size. Because of the greater weight of AA batteries, they are
contained in a separate case mounted on the rear of the head strap for
balance. A cable routes power from the rear battery pack to the
front located lamp.
- It has a variable focal length. The beam can be focused
tightly for a bright, narrow beam, or widely for broader illumination
that is less intense.
- It has three colored (red, green, blue) LEDs in addition to the
white LED. These colored LEDs are intended to reduce
interference with night vision.
- The white K2 LED has a very bright rating of 85 lumens.
This LED likely has a substantial current draw, hence the inclusion of
- The back of the battery pack has an amber light which makes the
wearer more visible from the rear at night.
The manufacturer did not provide the battery type for the information
in the following table. All of my measurements were made with
Duracell alkaline cells shipped with the unit.
|Year of manufacture:
|US $ 55.00
3.2 x 2 x 1 in
(82 x 51 x 29 mm)
2.8 x 2 x 1.7 in
(72 x 53 x 43 mm)
3.2 x 2 x 1 in
(85 x 51 x 29 mm)
2.8 x 2 x 1.7 in
(72 x 53 x 43 mm)
3.2 x 1.9 x 1.1 in
(81 x 49 x 29 mm)
2.8 x 2 x 1.7 in
(72 x 50 x 43 mm)
|Weight with battery:
|5 oz (155 g)
|5 oz (155 g)
|7.1 oz (202 g)
4.6 oz (128 g)
|16 hours high [Max output: 7 hours]
32 hours low
48 hours flashing
5mm (red, green, blue) LEDs:
500 hours red LED flashing
|16 hours high
32 hours low
48 hours flashing
5mm (red, green, blue) LEDs:
500 hours red LED flashing
|White: 85 lumens max
Red/Green/Blue: 1.8 lumens
|White: 85 lumens max
Red/Green/Blue: 1.8 lumens
Rear: 1 lumen
Note the discrepancy in the metric listed measurements between the
packaging and the website in RED.
The product label is closer to the listed inch dimensions.
Note that the weights given by the manufacturer seem to be closer to
what I measure without
batteries, though the documentation specifically says it is WITH
A brief note on the brightness specifications: the numbers given
by the manufacturer do not necessarily imply that the white light will
(85/1.8) times "brighter" than the color LEDs. A lumen is a
measurement of the total light output of a device, but the illumination
of a surface (like the trail in front of us as we hike) also depends on
how much area that light is spread out over. In fact, that is
precisely the object of the focus control on the K2: I can choose to
illuminate a small area very brightly, or spread the light out over a
larger area and get a dimmer illumination. I should actually see more
than a 47:1 difference in illumination between the colored LEDs and
the focused white LED because the white light is concentrated in
a small cone, but the colored light is spread out over a wide
area. Illumination is measured in
foot-candles (lux), and can be measured with a light meter.
LED modes: All of the LEDs can be turned, on, off and set to
white LED is the only one that has a brightness control: it has a high
and low mode.
The headlamp is stated to be "water resistant".
The lamp came packaged with a double-sided 4-color insert visible
through the plastic wrap. The insert contained the specifications
and operating instructions.
The instructions for inserting the (supplied) batteries were clear and
I had no problems installing them. I was happy to see no tools
were required; I liked the twist-lock closure.
The instructions for light operation are a little terse: "Press 3
seconds for Independent Operation of K2 LED or 05mm LEDs, Press Off if
stays at Any Mode over 3 seconds". It is actually a little more
complicated than that -- see next section.
One of my frustrations with the many lamps I own is the confusion I
often encounter with operating them. The manufacturers keep the
number of control switches to a minimum (often just one) to keep the
cost and weight down and to minimize places where water might
enter. As the number of options increases it gets more difficult
to understand and remember how to do it: do I press multiple times,
press and hold, etc. As an attempt to document how this lamp
works, see the following state chart:
K2 Focus Headlamp State Chart
How to read this chart: if the lamp button is initially pressed
and held for less than three seconds, the K2 white LED comes on at high
power. Subsequent short presses (< 3 seconds) cause the lamp
to first dim, then blink, then turn off.
If the lamp is in "White Mode", and the button is pressed and held for
>3 seconds the blue LED is lit. If the button is pressed again
before another 3 seconds elapses, the green LED is lit, and on to red
and blinking red. If any of the color LEDs is lit for more than 3
seconds, another button press turns the LED off. Any time the
lamp is in "Color Mode", pressing and holding the button for >3
seconds transitions to white mode and the white LED is brightly lit.
One thing that is apparent from the diagram is that in "White Mode", if
the lamp is turned off it always comes back on bright. I
typically use my lamps in low power mode to conserve batteries. I
wish the K2 Focus lamp remembered that it was in low or blink when last
used. Similarly, when using the color LEDs if turned off the
color always reverts to blue. I wish it remembered the color I
was using when turned off.
The control for
the rear light as shown in the photo at left is much simpler: it
operates similar to the "White Mode" but there is only one
intensity. The button is a little bit smaller than the front lamp
The width and intensity of the
white beam is controlled by a slide on
the bottom of the lamp. It is marked "1X" to "4X". I found
the control easy to locate and use.
two pictures of the lamp projected on a wall from about 10 ft (3.3 m):
The diameter of the circle on the left is about twice that of the one
on the right, so it has about 4x the area. It will be interesting
to see on the trail how I end up using the focus and how effective it
is in the field to zoom in/out on areas of interest.
I played around with the lamp the first night
after I received
it. It seemed like the front lamp switch was difficult for my
finger to find. It is not particularly big, nor does it protrude
very far. My other lamp has a switch many times the size of this
The lamp also can be tilted up or down. The tilt is easily
operated and there is a ratchet to keep the lamp from slipping down
The lamp fits comfortably on my head, despite its heft. It seems
that the balance from having the battery in the back and the lamp in
the front makes the relatively heavy weight of the lamp from the 3 AA
batteries quite bearable.
I am excited to use this lamp in the field. I have been looking
for a headlamp for some time that takes AA batteries for two reasons:
It took me a few minutes to learn to operate the controls, but now that
I understand it I appreciate the flexibility of its operation.
- They perform much better in the cold Minnesota winters.
Even lithium AAA batteries discharge quickly in frigid weather.
- I have several other devices that use AA batteries: GPS, digital
camera, and most recently a wood-fired stove that has a draft
fan. I want to standardize on AA batteries to allow common spares
and cannibalization in emergencies.
This concludes my
|March 28-April 4, 2009
||April 23-26, 2009
||May 1-3, 2009
||May 20-24, 2009
||June 11-14, 2009
|Ozark Trail in south-central Missouri located in
the Mark Twain National Forest
|North Country Trail (NCT), Heritage section in
||Superior Hiking Trail (SHT) between Split Rock
and Tettegouche state parks.
This was a car-camping trip, so only short sections of the trail were
hiked in and between the parks.
|Kekekabic Trail through the Boundary Waters
Canoe Area Wilderness (BWCAW) of northern Minnesota.
||North Country Trail (NCT), Chequamegon section
in northern Wisconsin
|925 ft to 1650 ft (280 m to 500 m)
||12500 to 1800 ft (380 to 550 m)
||650 ft to 1500 ft (200 m to 460 m)
||1450 ft to 2000 ft (440 m to 610 m)
||1050 ft to 1650 ft
(320 m to 500 m)
|Heavily forested with oak and hickory.
Many streams, one lake. Continual climb & descent of Ozark
||Heavily forested mix of deciduous and
pine. Streams, rivers, waterfalls, one beaver dam crossing.
||Heavily forested mix of birch and aspen.
Day 1 and 2 were ascent/descent trips, Day 3 was constant up-and-down.
||Burned and blowdown areas to dense forests of
poplar and spruce.
||Heavily forested with maple and pine.
Streams, lakes, bogs and beaver dams.
|Coldest night time low was 26 F (-3 C), warmest
daytime high was about 70F (21 C). Snowed the first night, had a
whole afternoon of rain on day five, rain showers off and on for
|Nightly lows near freezing, daytime highs
ranging from 45-65 F (7-18 C)
||Nightly lows just below freezing, daytime highs
ranging from 45-65 F (7-18 C). Day 3 was sunny.
||Lowest nighttime temperature was 29 F (-2 C),
highest daytime temperature of 80 F (27 C)
||Coldest nighttime low was 41 F (5 C), daytime
highs around 74 F (23 C), very light winds. Mostly sunny with
rain shower June 13.
Before departing on this trip I packed 6 spare Lithium AA
batteries. I was happy that ALL my electric-powered devices on
this trip (headlamp, camera, GPS and wood stove) used AA
batteries. My spares would be ready regardless of which devices
ran down their batteries.
Packing: I threw the lamp in the bottom of a side pocket in my
backpack and jammed stuff on top of it all week long. It never
turned on accidentally, never got in the way, and suffered no ill
effects from being exposed to rain and damp weather.
On this one-week backpacking trip I used the colored LEDs on the
headlamp every evening for my nightly tree-watering excursions.
One of the first things I noticed was "why does the blue light come on
first?" After all, don't photographers use a red lamp in the
darkroom, and isn't it a red lamp that minimizes loss of night
vision? Perhaps the designers thought that the red LED would be
useful in flashing mode as an emergency beacon, and to be consistent
with the white mode the red LED had to be last in the sequence. I
was also surprised by how focused the color LEDs were despite the fact
they do not have an accessory lens to focus the beam. Obviously,
a lens is built directly into the LEDs, and they are quite effective.
It did seem that all the color LEDs did a good job of retaining my
night vision. After I turned the lamp off I was able to
immediately see well at night. There is no doubt a difference
between colors in night vision retention, but it was beyond my ability
to detect the difference in normal operation.
To keep the headlamp accessible I hung it from the ridge line of my
shelter, the battery pack on one side of the line, the lamp on the
other, and the strap looped over the top. This worked well: the
lamp stayed in place, was easy to reach, and the light pointed down for
task illumination. I did find the on/off button difficult to find
with my fingers in the dark. It is not a problem when the lamp is
on my head as it is positioned right at the top, but when the headlamp
is not on my head I fumbled for some seconds to find the button.
To me, the button seems small and is not raised enough from the lamp
housing to create a good tactile sense.
I tried using the various colors, and I didn't notice an appreciable
different in visibility with the various colors until the night it
rained. The blue and green lights really showed wet versus dry
vegetation, whereas with the red LED the two were indistinguishable.
I used the bright white light every morning to read my
thermometer. As I've grown older my reading vision has diminished
and I now need reading glasses, but with the bright K2 LED on High with
the beam focused as narrow as possible I could read the temperature
without my glasses. Nice.
Night falls on the Ozark Trail
On my last morning on the trail I packed up and hiked back to my car
before the sun was up. I used the white light on High with the
wide beam for breaking camp. I found that while breaking camp I
preferred the wider to the narrow beam because it gave me a wider field
of view of my gear. On the hike back to the car the sky was
starting to lighten up, so I switched to the narrow beam to illuminate
the treadway. The light worked great for that, but I found the
"bouncing" of the narrow beam somewhat distracting, and preferred a
wider but less intense beam.
NCT - April
I continued to use the headlamp for my nightly tree watering
outings. I find that I prefer the red LED for this purpose, and I
wish it was the first selection in color mode. The green and blue
colors just seem bizarre to me.
On night 3 of this trip I pitched my tent about 100 ft (30 m) from the
main campsite as all the tent pads there had been taken by my
compatriots before I set up. We stayed up until well after dark
with a campfire, and I used the lamp to follow the trail back to my
tent. I found I preferred the wide beam setting for this purpose
to light up the width of the trail.
My fellow campers were astounded at how bright this light was. It
made their headlamps look like a weak glow.
This was a car camping trip (Finland State Forest campground) and the
was packed in the pocket of a duffel bag instead of in my
backpack. When I arrived at the campground and opened up the
pocket, I noticed the blue LED was on, but the lamp was not on when I
packed it the night before. I could only conclude that bouncing
around in the pocket had bumped the on/off switch causing the lamp to
inadvertently turn on. This is not good, as it could result in
battery drain. Clearly, the switch should be designed to prevent
this from happening.
I used the light in the evenings as we returned back to our campsite
nights very late. On the second evening I had to take an evening
stroll to the latrine in the dark, which was about a 500 ft (150 m)
walk down a dark snow-covered road. I experimented with various
LED colors to see which one worked better. One thing I noticed is
that the blue LED will not light up a yellow reflective sign.
This makes sense, as yellow reflects only green and red. When I
got back to my car I noticed that the red LED was the only one that
would light up the red reflectors on my car, and that also makes sense.
On the second evening a camper pulled in to the neighboring spot and
began to attempt to set up her tent in the dark. I offered her
the use of the headlamp, which she gratefully accepted saying how silly
of her to forget her lamp. She really appreciated the bright K2
LED and completed setting up her tent with no difficulties using the
headlamp. It was quite interesting to watch someone else use the
headlamp - it really is very bright and effective at illuminating a
large work area.
Morning mist by the Boundary Waters Kekekabic Trail
By late May the days start getting pretty long near the Canadian
border. The sky did not get dark until 9PM, and began getting
light at about 4AM. The only use on this trip for the headlamp
was illuminating my night time tree watering excursions, which I did
with the blue LED to conserve battery power. The headlamp handled
this task well. On this trip I began to tire a bit of the weight
of the headlamp, and to not enjoy the weight distributed between the
lamp unit and battery pack. It just seemed to be a lot more
weight penalty than the lighting value I was actually using. On
the other hand I was getting used to using the non-red LED lights -
they no longer seemed bizarre to me. In fact, they seemed
brighter than the red light.
NCT - June
The headlamp got more use on this trip despite the long day length as
the people I was hiking with liked to stay up late around a campfire
and talk. I loaned the headlamp on the first night to a fellow
camper who had to hike the 0.4 miles (0.6 km) to the parking lot and
back after dark. It was useful to watch someone else use the lamp
at night on the trail hiking with several other people with
headlamps. The K2 was incredibly brighter than any other headlamp
in the group.
I noticed on this trip that the light switch is back-illuminated only
when the red LED is used. The back-light is handy for finding the
switch to turn the light off, and it is logical that only the red LED
illuminates the switch as it is positioned directly beneath it.
The K2 Focus headlamp provides fantastic illumination, but at the cost
of weight. My feeling so far is that this is a lamp for my winter
use when there are more hours of darkness and larger batteries are
needed due to cold weather impact on their performance. I really
wish I had been testing this lamp in January and February. The
battery life has been good so far - after five backpacking trips I am
still on the original cells.
Areas for improvement:
- Very bright high beam
- Variable beam width for detailed task lighting versus wider trail
- Color LED's retain night vision but are bright enough to
- AA batteries for commonality and long burn times
- On/off switch for the lamp is hard to find when the headlamp is
not worn on the head
- Too easy for jostling to accidentally turn the lamp on and drain
- I would prefer the red LED be the first setting in color mode
- Quite heavy, especially with the 3 AA batteries
Long Term Report
|July 11-12, 2009
||August 1-2, 2009
|Mt Lemmon just north of Tucson -
Mt Lemmon Trail (section of Arizona Trail)
||Mt Lemmon, Wilderness of Rocks Trail
|7450 ft to 9100 ft
(2271 m to 2774 m)
|7000 ft to 8100 ft
(2100 m to 2500 m)
|Mountain meadows, rocky ridges
and trail. All descent/ascent, almost no level hiking.
||Pine forests, rocky trail and outcroppings
|Nighttime low of 60F (15 C),
daytime high at lower altitude of 88 F (31 C)
||Nighttime low of 60F (15 C),
daytime high at lower altitude of 90 F (32 C)
Mt Lemmon - Mt Lemmon Trail
On July 5 I moved to Tucson, Arizona. The K2 headlamp survived
the move with no ill effects. This locale should allow a bit
better testing of the headlamp because Arizona does not observe
daylight savings time, so it gets dark at least an hour earlier than is
typical elsewhere in the U.S. during the summer months. Also
day length is not as extended during the summer in southern latitudes.
Sure enough, on my first Arizona backpacking outing it got pretty dark
at about 8:30PM. The above photo shows the sunset about an hour
earlier. I had to break out the headlamp for final camp
chores, which it worked well for. It was also used during the
usual nighttime excursions with no issues.
7:30 PM sunset on Mt Lemmon, Oro Valley below
Mt Lemmon - Wilderness of Rocks Trail
The headlamp was used for a midnight excursion that included getting a
drink of water from my hydration reservoir hanging from a nearby
tree. I used the lamp in the blue light mode. It was plenty
bright for my chores and getting re-settled in my shelter.
Use for jogging/running
When I moved to Tucson I had to quickly adapt my running
schedule -- everyone here runs/walks/bikes before the sun comes up in
summer to avoid the heat of the day. On several occasions I went
out early enough (4:30 AM) that it was still pitch dark. Tucson
also has very strong light pollution rules, and many streets do not
have street lights. The K2 headlamp has come in handy for this
I have found that the white low-power beam is adequate for use while
running on streets and sidewalks, even when used in the wide beam
mode. This is also the only application where I used the rear red
"tail" lamp. I found it very comforting when running on a street
to know that I had a red light on to better help auto drivers to see me.
The weight of the K2 headlamp was not an issue for this
application. The split of the weight between front and rear kept
the lamp from sliding down in the front when bouncing along.
Overall I have been very happy using the K2 headlamp for jogging in the
dark, no complaints whatsoever.
Battery life has been excellent. I am still using the cells
supplied with the unit.
My feelings and experiences have not changed in substance since filing
my Field Report. The question I now ask myself is "will I
continue to use the K2 headlamp after the test period is
My opinion is "yes, for selected trips". I will likely leave the
headlamp at home on summer trips where daylight supplies most of my
needs. The one exception might be if I head out for a trip on a
Friday night after work and am likely to arrive at the trailhead at
dusk. In this case I would take the headlamp to make sure I had
enough light to make my way along the initial trail section and set up
camp in the dark.
I am likely to use the K2 headlamp in winter, even here in
Arizona. As the days get shorter I will be performing more
activities in the dark. I've come to appreciate the bright light
this headlamp supplies, yet I can conserve battery power using the
color LED lights when appropriate. The AA battery pack is heavy,
but acts as a set of backup cells for my camera and GPS which mitigates
the weight penalty.
Many thanks to Essential Gear
and BackpackGearTest.org for the
test this product.
Read more reviews of Essential Gear gear
Read more gear reviews by Kurt Papke