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

Black Diamond Cosmo

Long Term Report - September 26th, 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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Field Locations and Conditions

Since the Black Diamond Cosmo's arrival four months ago I have used it on a dozen or more nighttime treks and on six overnight backpacking or car camping nights. Locations included Sonoran Desert mountain ranges in Phoenix, AZ and pine forests near Flagstaff, Payson and Prescott, AZ. Conditions varied between dry and hot on the desert trails and cool and rainy on two of the Northern Arizona trips. Elevations ranged between 1,400 ft (430 m) up to as high as 7,500 ft (2,300 m) with temperatures in the upper 90's (36 C) or in the mid to upper 40's (8 C) respectively.

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Long Term Findings

I enjoyed testing the Cosmo. It has been a very useful piece of gear and because of its compact size it's perfect as a "just in case light" so I find myself tossing it in my pack even if I'm not planning to be out overnight. When car camping I brought it purely for the convenience of hands free light around camp and contrary to our bulky heavy duty camping flashlight, the Cosmo was easy to toss in my jacket pocket. At under 3 oz (85 g) I'm content with its overall comfort as well. The band is nonrestrictive and has remained soft and stretchy despite repeated doses of sweat. It has not retained any odors, stiffened up or become difficult to adjust. I also have not had any problems with the band slipping after my initial size adjustment.

Beyond its usefulness and continued comfort I am still pleased with the little light's bulb power. The lowest setting worked well for nearly every task for which I have needed a light. This has involved all after dark camp chores, most night hiking, reading in my tent and looking at maps while on trail. I found the brighter settings helpful when looking for trail junctions, spotting family members and my dog in the dark across camp, and illuminating street signs from my vehicle on a dark country road. I'm guessing I've had the Cosmo on for about 25 hours with all uses put together and I am still using the same set of batteries I placed in the headlamp when I received it. (The exception to this is when I placed a new set of batteries in the light to verify the distances I wrote about previously in my Field Report.) The last two times I have worn the Cosmo I noticed the light getting slightly dimmer so although I have not needed to change the batteries up to this point, I can tell this will be necessary soon. When I put new batteries in during my second distance test the output looked very strong so the bulbs, as far as I can tell, aren't showing any signs of weakening.

My only area of contention stems from what I consider an overly touchy on/off switch. (I mentioned this in more detail in my Field Report.) I'm still getting used to it and I often over shoot the setting I want. I definitely think it's more user error than an equipment malfunction but that doesn't make it any less frustrating.

There were two aspects of the Cosmo I did not fully test during the initial two months. The first of these was my ability to change the batteries while wearing gloves and/or without light. I tried this while car camping with my son in Prescott National Forest. We had about an hour of rain in the early evening so while waiting it out in our tent I tried changing the batteries while wearing a set of liner style gloves. I was able to open the back of the lamp housing with ease due to Black Diamond's very smart design. The battery cover is removed by bending the lamp bracket, which is the piece the head band slides through, up past ninety degrees until the battery door pops open. The lamp bracket provides a very good grab point so performing this task with gloved fingers was not a problem. Removing the batteries was far more challenging since I could not get a grip on the little AAA's with my thicker gloved fingers. I had to remove one glove briefly to dislodge the batteries. Returning them to their slots with gloves on was not a problem, however.

Later that evening after my son fell asleep I played with the Cosmo again, this time to see how easily I could change the batteries in the dark. Again, because of the simple design it was a snap to open the housing and reach the batteries. Since I could not see I had to feel my way through the exercise of removing the batteries and replacing them. The only area of contention was which direction to face each battery in its respective slot. My solution was to turn on the light so I could see the direction of each batteries then I turned off the light, took the batteries out and replaced them. This option worked because the light was still operable, however, if I was in the same situation with a completely dead set of batteries, I would have a bit of trial and error to run through if I could not remember which way each one faced.

The other aspect of the Cosmo I wanted to readdress in this final report was the large discrepancy I encountered when testing the light's functional distance. With the help of my husband I reported in my Field Report that the light was most effective using the maximum setting under 30 ft (9 m). With in that range he could show different number amounts on his fingers and I could see clearly what that number was. Beyond 36 ft (11 m) I was able to see him standing there but could not make out his face or other identifying features. My results fell quite a bit short of Black Diamond's amount of 59 ft (18 m) on the max setting (with fresh batteries). When I conducted this test I had already been using the headlamp for almost two months so I decided in order to give the manufacturer's claim a fair shake I needed to redo my test with fresh batteries. I did and there was an improvement. This time around I was able to see how many fingers my husband was holding up at just under 40 ft (12 m) and I could still make him out at 52 ft (16 m). Again, it is important to note I have no idea how Black Diamond came up with their numbers but I tried to think of a test that was somewhat practical and easy to repeat.

I then used the light with the fresh batteries on trail to search for my hiking partner. The distance at which I could make her out was again right around 52 ft (16 m). When used to locate a trail marker I could easily spot chevrons or signs using luminescent paint from beyond 59 ft (18 m) but anything without reflective materials was difficult to make out past about 45 ft (14 m). The strobe wasn't used much other than when I over clicked the minimum setting and found myself blinking. I did test it to see how far I could see the light while I was testing the functional distance and the results were good. With fresh batteries I was able to see the strobe at well over 150 ft (46 m) away. I think given this it would be quite helpful in an emergency situation.

Thank you Backpackgeartest.org and Black Diamond for the opportunity to be part of this test series. I think the Cosmo is a neat little light and I appreciate the chance to run it through its paces.

Jamie J. DeBenedetto
September, 26th 2006

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