REASONS TO BUY
Lightweight
Small size
Excellent flood lighting
REASONS TO AVOID
Below average spot beam
Disappointing low-mode battery life
Black Diamond Cosmo Review
A good light, but caught in a no-mans land between better lights and cheaper lights
Credit: Abriah Wofford
By Jediah Porter ⋅ Review Editor ⋅ May 28, 2018
Contributions From: RJ Spurrier
RELATED: The Hunt for the Best Headlamps
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
 This Product
Black Diamond Cosmo | |||||
|---|---|---|---|---|---|
| Awards |  Best Headlamp for General Purpose Use | ||||
| Price | $40 List Check Amazon (on sale!) | $50 List Check Amazon (on sale!) | $29 List | $25 List Check REI (on sale!) | $25 List Check Price at REI |
Overall Score  |
|||||
| Star Rating | |||||
| Bottom Line | A good light, but caught in a no-mans land between better lights and cheaper lights | Previously one of our favorites, but hasn't kept pace with competitor's innovations | The Yalumi is a good light, at a good price, that provides basic functionality | For $20, the Tikkina offers impressive performance at a great price, that will meet most people's needs | Offers great close proximity lighting at a budget price |
| Rating Categories | Black Diamond Cosmo | Coast HL7 | Yalumi LED 140-Lumen | Petzl Tikkina | Black Diamond Astro |
| Trail Finding (35%) | |||||
| Close Proximity (20%) | |||||
| Battery Life (15%) | |||||
| Weight (15%) | |||||
| Ease of Use (15%) | |||||
| Specifications | Black Diamond Cosmo | Coast HL7 | Yalumi LED 140-Lumen | Petzl Tikkina | Black Diamond Astro |
| Measured Beam Distance | 66 m | 112 m | 94 m | 62 m | 38 m |
| Claimed Distance | 65 m | 119 m | 90 m | 55 m | 35 m |
| Measured High Mode Run-time (ANSI) | 3.9 hrs | 3.1 hrs | 4.3 hrs | 3.5 hrs | 4.8 hrs |
| Claimed High Mode Run-time | 45 hrs | 1.5 hrs | Not specified | 60 hrs | 20 hrs |
| Measured Low Mode Run-time | 39 hrs | 25 hrs | 47 hrs | 223 hrs | 95 hrs |
| Claimed Low Mode Run-time | 180 hrs | 70 hrs | 100 hrs | 220 hrs | 80 hrs |
| Measured Weight | 3 oz, 86 g | 4.5 oz, 127 g | 2.7 oz, 77 g | 2.9 oz, 83 g | 3 oz, 86 g |
| Battery Type | 3 AAA | 3 AAA | 3 AAA | 3 AAA | 3 AAA |
| Water Resistance | IPX8 waterproof beyond one meter | water resistant | IPX4 splash proof | IPX4 splash proof | IPX4 splash proof |
| Manuf Claimed Lumens | 200 lumens | 285 lumens | 140 lumens | 150 lumens | 150 lumens |
| Beam Type | flood/spot, dimmable | flood/spot | flood/spot | flood | flood, dimmable |
| Red Light | yes | no | yes | no | no |
| On Switch Lock | yes | no | no | no | yes |
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.
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
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
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