Reviews > Lighting > Headlamps - LED > Black Diamond Cosmo > Jamie J. DeBenedetto > Field Report

Black Diamond Cosmo

Field Report - July 30th, 2006

Reviewer's Information

Background/Experience

I began backpacking eighteen years ago after tagging along with my dad to various wild places in Arizona and California as a child. At present I hike in some capacity about fifteen times a month, mostly in Arizona with either the Canine Hiking Club of AZ or with my family. I prefer to sleep in a hammock and I gravitate toward multifunctional gear that will enhance my comfort level for minimal weight. I consider myself a lightweight packer but not ultralight. My total pack weight year round is rarely above 25 lbs (11 kg) for outings of two to three days.

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Product Information

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Product Description

The Black Diamond Cosmo is a lightweight LED headlamp with a removable headband. For a more detailed description of this item please see my Initial Report.

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Experiences Thus Far

I received the Black Diamond Cosmo in May of 2006. Since then I have used it on seven evening hikes, one overnight backpacking trip and one two-night car camping excursion with my family. The following are my thoughts and observations to this point in the testing process.

Desert Night Hikes at North Mountain Park

North Mountain is a local desert recreation area located in the heart of Phoenix. The path I take is part desert, part paved road and due to a fairly steep grade it makes for a quick little workout. Elevation ranges between 1,400 ft (430 m) at the trailhead up to 2,100 ft (640 m) at the top. Summer days are not hospitable for hiking here in the Southwest so all of these hikes took place in the post sunset hours when the temperatures had dropped back down into the upper 90's F (36 C). I have yet to experience rain or other inclement weather on any of these evening jaunts.

The glow from the city makes it possible to hike North Mtn. without a light but since the rattlesnakes and scorpions are more active this time of year and I have the Cosmo to test, I have been pretty diligent about using the headlamp each time I've trudged up to the summit lately. On the first few outings I experimented with the different brightness settings but I quickly found the lowest puts off plenty of light to see the trail and surrounding nooks and crannies where critters might be hiding. In fact, the other two settings are so bright I kept blinding my hiking partner. The tilt feature, I found, was a nice solution for my affinity for direct eye contact. My hiking partner has expressed her thanks for this option on more than one occasion as well.

I am pleased with the comfort of the Cosmo so far. The band is not at all obtrusive and it hasn't slipped or twisted since I found the correct adjustment for my noggin. It does get extremely sweaty in a very short period of time though, which I don't like, but I'm not really sure how this could be improved. Most importantly on this point, the band fabric doesn't irritate my skin, wet or dry. The plastic piece used to connect the headlamp to the headband lies flush against my forehead and for the more part is hardly noticeable. The headlamp itself is also quite inconspicuous, which isn't surprising at only 2.3 oz (65 g).

On a slightly negative note, I am having a hard time getting used to the on/off button. I seam to be incapable of depressing it lightly so as not to click past the setting I want. Or my other continued failing is to push too hard and turn the light off completely. I'm not sure if the button is a bit touchy or if it's solely operator error. Either way, I hope I will get better with this after more use.

Overnight backpack into the Aravaipa Canyon Wilderness

Aravaipa Canyon is northeast of Tucson, AZ, elevation 2,600 ft (800 m). It is a lush riparian area surrounded by typical Sonoran Desert landscape. We had a nighttime low of about 60 F (16 C) and daytime highs up around 95 F (35 C) or slightly higher when I was there at the end of May. Weather conditions were clear, dry and for the most part calm with an occasional light breeze in the afternoon and early evening.

The BD Cosmo was the only light source I brought on this trip and I ended up using it quite a lot more than I thought I would. Due to the high daytime temperatures it took a few hours after sunset for my shelter, a Tarptent Rainbow, to cool down enough for me to sleep comfortably. Instead of sweating it out for a couple of hours I chose to sit out on a sandbar near the creek and watch the bats duke it out for insects. The Cosmo was a great tool to have along. Rattlesnakes are abundant in this area so I needed a good light to safely navigate my way back and forth from the beach to the tent site. I also found the brightest setting to be really handy for nocturnal critter spotting. My sister and I saw several sets of eyes across the creek curiously watching us and a flash of an owl as it swooped off a near by saguaro cactus.

Again, I found the lowest setting perfectly ample for nearly all tasks I needed to do around camp before bed. It was especially sufficient inside the shelter when a higher light output would just be plain rude to my tentmate. Not as much a necessity as the LED settings but I found the marigold color was nice to have as I was fumbling around for the light in the middle of the night and when I was looking for it in my pack as dusk fell. Our night at Aravaipa was moonless so it was comforting to know if I dropped the Cosmo I would likely be able to find it again without too much hunting.

Car camping on the Mogollon Rim

The Mogollon Rim is a unique geologic feature that to all intents and purposes cuts Arizona in half, north from south. The higher elevations of this primarily pine covered escarpment are dotted with lakes and an endless supply of recreational choices. The campground where my family and I stayed was nestled in at an elevation of about 7,500 ft (2,300 m). The temperatures were in the upper 70's F (25 C) during the day and in the mid 40's F (7 C) at night. We did experience breezy conditions all three days but no precipitation, unfortunately.

The Cosmo was used in the evening on trips to and from the bathroom, around camp to find campfire munchies and secure edibles for the night, and in our tent to get my kids ready for bed. It performed great for all these tasks. I love the convenience of the light. I could wear it for several hours and not even notice its presence. I also really enjoyed having my hands free, especially when tending to the needs of my young children. The most notable experience I had with the LED on this trip is the realization of just how far the beam penetrates through the darkness when it's on the max setting. The power of the four little LED bulbs became glaringly apparent while I was walking through the dark woods to visit a part of our family in a neighboring campsite. Because I had been using the Cosmo on the minimum setting on most of my previous excursions I decided to give the maximum setting a go to see how well it performed. My path was lit up like Christmas. In fact, it became quite a joke to my in-laws in the next campsite over. They lovingly ribbed me about bringing a spot light to camp and about all the light pollution distrupting their starry view.

With the help of my husband I tried to gage the brightest setting's functional distance. I had him stand in one place as I backed away, at various points I would ask him to show me a number on his fingers, then I would try to focus in on his hand with the light and tell him the number. I was able to get just over 30 ft (9 m) away before the light was no longer effective. I backed away an additional 6 feet (2 m) and was still able to make my husband out but all I could tell is there was a person standing there. I could not see his face or body features well enough to identify him with any clarity at this distance.

The comparable distance (with fresh batteries) from the Black Diamond information is 59 ft (18 m) for the maximum setting. I did not have fresh batteries, but regardless I'm having a hard time believing this light would be useful at 59 ft (18 m). The informational sheet included with the Cosmo that I'm taking these numbers from does not elaborate on how Black Diamond came up with their distance totals for the three brightness settings. I think it's only fair to say that I'm basing my measurement on what I consider a "useful" distance. This means if I am in the field at night searching for a trail marker or a hiking partner, I believe given my little test I would not be able to clearly see either unless I was within 36 ft (11 m) of them. During the long-term testing phase I am going to test these findings using fresh batteries while looking for a trail sign or marker. Because my measurement is so far off from BD's I want to give it a second shot before I post my final results on this matter.

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Proposed Test Strategy for the Remaining Two Months

Fit - I think I have worn the LED long enough at this point to have an accurate picture of this aspect, however, I will continue to be watchful for any new information and report any changes in my final report.

User Friendliness - This involves attaching and removing the band, changing batteries, cleaning the unit and drying it if it gets wet. In the field I will assess User Friendliness features by performing all maintenance duties with and without gloves on, if possible with cold fingers and with and without sweaty hands. I will try to use it while doing as many tasks as possible and in varying conditions to see how it fairs.

Headlamp - The Cosmo has three brightness settings, a strobe feature and boasts a 90 degree tilt capability. The only area I have yet to challenge regarding the headlamp is the strobe feature. I will try to use this in some capacity during the final two months of testing and report on my findings. Specifically I am interested in the distance and which the strobe can be seen and how effective it would be a signaling device.

Durability - As it relates to abrasions, drops, sweat, and LED life. I will do a few drop tests at the end of the test period if I haven't already dropped it on accident during use. I will also evaluate how the headband holds up to repeated use, adjustments and sweat. Black Diamond states it's good for "go-anywhere use", I will also look for other creative ways to integrate the light into my non-backpacking life to get a feel for these "go-anywhere" abilities.

Thank you Backpackgeartest.org and Black Diamond for the opportunity to be part of this test series.

Jamie J. DeBenedetto
July 28th, 2006

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Reviews > Lighting > Headlamps - LED > Black Diamond Cosmo > Jamie J. DeBenedetto > Field Report