Black Diamond Ion and Iota Headlamps Review


Product name: Black Diamond Ion and Iota Headlamps

Basic summary: Black Diamond makes a big hit by going small. The Ion is the company’s smallest, lightest and most compact fully functional headlamp that runs on AAA batteries, with amazing battery life and more than enough brightness to move you safely down the trail. The Iota is a new lamp this winter, and is the smallest and lightest rechargeable light Black Diamond offers; it has shorter burn time but 50% greater brightness than the Ion. Both lamps are available at low price points that are an excellent value for their functional utility.

Black Diamond Ion: $24.95
Black Diamond Iota: $39.95

Black Diamond Ion:

  • Weight: 55g
  • Brightness: 100 lumens
  • Max distance: 38m
  • Batteries: 2 AAA
  • Battery life: 6 hours (high setting), 180 hours (low setting)
  • Dimming function
  • Strobe function
  • Red night vision mode
  • Battery lockout
  • IPX 8 – waterproof

Black Diamond Iota:

  • Weight: 56g
  • Brightness: 150 lumens
  • Max distance: 40m
  • Batteries: rechargeable lithium ion
  • Battery life: 2 hours (high setting), 40 hours (low)
  • Dimming function
  • Strobe function
  • PowerTap technology to adjust brightness
  • Three-level power meter
  • Battery lockout
  • IPX 4 – protected against sprayed water from any angle

Deep dive:

Regarding headlamps, many trail runners fixate on a simple fallacy: that brighter is inherently better. And to be sure, there’s nothing like a superbright torch to illuminate every bump on the path. However, there’s also a lot to be said for small, dependable lights that can either simplify your needs or bail you out of an emergency – and this fall, the two Black Diamond lights we tested did each of those things.

Here’s example #1: We ran a 50-mile race in December that started at 5 a.m., ensuring that we’d be running for nearly two full hours before sunrise. From a logistical standpoint, we didn’t want to leave a headlamp at an aid station after sunrise, which would require a long delay in retrieving it after the race. We used the new Black Diamond Iota which provided plenty of light to run at pace in the dark, then tucked it into a pocket and forgot about it for the rest of the day.

Example #2: At a 100-miler in September, we estimated wrong on how many miles we would cover before nightfall – meaning that darkness set in about 6 miles before we reached the aid station with our high-powered headlamp in a drop bag. Fortunately, we were smart enough to carry the Black Diamond Ion into our vest pocket … and its illumination was enough to get us safely to the aid station without problems. Those six miles were more than enough to justify carrying them for the previous 58 – especially because the Ion was hardly noticeable for the entire time.

That’s the appeal of each of these lamps: they’re cheap insurance against your own stupidity, and they’re so compact and light that it’s literally no trouble to stuff them into a pocket when they’re not in use. There are a handful of functional and operational differences between the two, but both come with impressive feature sets and offer great performance value at the low end of the price spectrum.

Black Diamond Ion

The Ion is redesigned this winter, receiving an increase in brightness from 80 lumens to 100, and a new all-purpose push-button switch that replaces the somewhat tricky swipe-activated system on the previous model. You push the button once to turn the lamp on, then press and hold to activate the dimmer: the double-power LED scrolls from bright to dim and back again until you release it at your desired intensity. An initial press and hold switches from regular LED mode to red mode if you want to preserve night vision. A prolonged press triggers the battery lockout feature to prevent the lamp from accidentally turning on in your pocket; a short blinking light makes it easy to tell when lockout mode is activated. The Ion runs on two AAA alkaline batteries, with an impressive burn time on high and a crazy-long lifespan (180 hours) on a lower setting.

Black Diamond Iota

By comparison, the Iota uses rechargeable batteries, and is one of the smallest rechargeable lamps you’ll find. It burns significantly brighter than the Ion – 150 lumens compared to 100 – but as is the case with rechargeable batteries, its burn time is substantially less. Functionally, it has the same multi-function push button mechanism on top of the housing that controls on/off, dimming, and battery lock activation – although there isn’t a red light mode on the Iota like there is on the Ion. Another difference is that the Iota features a three-color battery life gauge that isn’t available in the Ion. One cool innovation on the Iota is the PowerTap function, which switches the lamp to full brightness simply by tapping the side of the housing; this is helpful when you want a quick burst of light to check out that noise in the bushes or to alert an oncoming car.


Choosing between these two lamps probably comes down to whether or not you want rechargeable batteries and have the capacity to recharge them as needed between uses. Otherwise, either of these lamps are almost must-have items to provide you with a dependable and convenient light source in a super-compact and convenient package.


About Author

Donald is a physical therapist, California native, barefoot aficionado, and father of three with more than 25 years of experience in endurance sports. He was a collegiate rower at UCLA, then dabbled in marathons and Ironman-distance triathlons before falling in love with ultras in the early 2000s. His favorite locations to run include Marin County, CA, and the Sierra Nevada mountains, and he loves exploring America's National Parks. When he's not training for ultramarathons, he enjoys hiking or slacklining with his family in Monterey County, CA.

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