The world's most in-depth and scientific reviews of outdoor gear

Black Diamond Cosmo Review

A good light, but caught in a no-mans land between better lights and cheaper lights
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Price:  $30 List | Check Price at Amazon
Compare prices at 2 resellers
Pros:  Lightweight, small size, excellent flood lighting
Cons:  Below average spot beam, disappointing low-mode battery life
Manufacturer:   Black Diamond
By Jediah Porter and RJ Spurrier  ⋅  May 28, 2018
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58
OVERALL
SCORE


RANKED
#11 of 27
  • Trail Finding - 35% 4
  • Close Proximity - 20% 9
  • Battery Life - 15% 5
  • Weight - 15% 6
  • Ease of Use - 15% 6

Our Verdict

While this is a good headlamp, we implore you to spend another $10 and get something like the Black Diamond Spot which has much better beam brightness and quality combined with a very respectable battery life. The Cosmo is a middle of the road kind of light. It offers average performance and average battery life at an average price. If you are on a budget, look to the Petzl Tikkina which scored slightly better for a fraction of the price.


Compare to Similar Products

 
Awards  Top Pick Award Editors' Choice Award Editors' Choice Award  
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$89 List$36.73 at REI
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$34.95 at Amazon
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$43.12 at Amazon
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Pros Lightweight, small size, excellent flood lightingBright wide beam, good battery life, durable design, rechargeableExcellent trail finding and close proximity beam, waterproof, above average battery lifeExcellent spot light capability, wide evenly lit flood beam, above average in most waysExcellent brightness and beam control, often available online at discount
Cons Below average spot beam, disappointing low-mode battery lifeExpensive, 18650 Li-ion battery is not included, heavier than averageMore expensive, heavier than average, claimed battery life is very misleadingBelow average battery life, claimed battery life is wildly misleading, single button hard to use, lame waterproofingAverage battery life, heavier and bulkier than most
Bottom Line A good light, but caught in a no-mans land between better lights and cheaper lightsAn impressive, powerful light in a small package that won't disappoint if you can get past the priceA durable light that will last for years with a bright high-quality beam, slightly higher in cost and weightA quality, durable, and bright light that hits the sweet spot for most people's needs, despite dubious marketing claimsPreviously one of our favorites, but hasn't kept pace with competitor's innovations
Rating Categories Black Diamond Cosmo Zebralight H600w Mk IV Black Diamond Storm Black Diamond Spot Coast HL7
Trail Finding (35%)
10
0
4
10
0
9
10
0
9
10
0
8
10
0
8
Close Proximity (20%)
10
0
9
10
0
7
10
0
8
10
0
9
10
0
7
Battery Life (15%)
10
0
5
10
0
9
10
0
6
10
0
4
10
0
5
Weight (15%)
10
0
6
10
0
4
10
0
5
10
0
6
10
0
4
Ease Of Use (15%)
10
0
6
10
0
9
10
0
6
10
0
6
10
0
8
Specs Black Diamond Cosmo Zebralight H600w... Black Diamond Storm Black Diamond Spot Coast HL7
Measured Beam Distance 66 m 121 m 91 m 94 m 112 m
Claimed Distance 65 m Not specified 85 m 80 m 119 m
Measured High Mode Run-time (ANSI) 3.9 hrs 3.1 hrs 5 hrs 2.9 hrs 3.1 hrs
Claimed High Mode Run-time 45 hrs 2.9 hrs 40 hrs 30 hrs 1.5 hrs
Measured Low Mode Run-time 39 hrs 232 hrs 42 hrs 9.7 hrs 25 hrs
Claimed Low Mode Run-time 180 hrs 203 hrs 120 hrs 175 hrs 70 hrs
Measured Weight 3 oz, 86 g 4.5 oz, 127 g 4 oz, 112 g 3.1 oz, 89 g 4.5 oz, 127 g
Battery Type 3 AAA 18650 rechargeable Li-ion 4 AAA 3 AAA 3 AAA
Water Resistance IPX8 waterproof beyond one meter IPX8 waterproof to 2 meters, 30 minutes IP67 waterproof to one meter and dustproof Splash proof (dubious IPX8 claim) water resistant
Manuf Claimed Lumens 200 lumens 1400 lumens 350 lumens 300 lumens 285 lumens
Beam Type flood/spot, dimmable flood flood/spot flood/spot flood/spot
Red Light yes no yes, red/green/blue night-vision modes yes no
On Switch Lock yes yes (tailcap lockout) yes yes no

Our Analysis and Test Results

The Cosmo is a solid headlamp with good performance overall, and excellent flood lighting for close proximity use. At $30 list, it falls into a tough price range where a little more money gets you a much higher performance headlamp, like the Spot, and products like the Tikkina offer better overall performance for 33% lower price.

Performance Comparison



Trail Finding


A score of 4 for trail finding is disappointing for a $30 headlamp, and most similarly priced competitors offer significantly better performance.


Beam Distance Photos
Beam photo of Black Diamond Cosmo
Beam photo of Black Diamond Spot

Black Diamond Cosmo
Black Diamond Spot

In comparing the Cosmo (above left) and Black Diamond Spot (right), two products from the same manufacturer and priced just $10 apart, it is remarkable that they can vary so much. The Spot casts a much superior distance beam.

Close Proximity


The strongest performance from the Cosmo is when used around camp, or in the tent, for close proximity work. The flood beam is one of the very best of all headlamps we tested, wide, evenly lit, and dimmable from nice soft lighting for use in the tent, and brighter for use in the camp kitchen. It is worth noting that the Black Diamond Astro offers a flood beam that is nearly as good, at a price 33% lower.



Battery Life


Battery life is where the Cosmo edges slightly ahead of the Spot.



Weight


At 3.0 ounces or 86 grams, this is a compact but not ultralight headlamp. It is about the same weight as the Spot. For comparison, the featherweight champion Petzl e+LITE is less than a third the weight at 27 g.


Conclusion


This is a solid light but tough to justify buying. At $30 list it is wedged between competitors that either score much better for another $6-10 or offer the same or better performance for lower cost. The BD Spot, for example, performs significantly better for only $10 more. It has a nearly identical form factor and mass with a much better beam. On the low-end, the Petzl Tikkina offers better all-around performance at 33% lower cost.


Jediah Porter and RJ Spurrier