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Black Diamond Iota

rated 4.0 of 5 stars
photo: Black Diamond Iota headlamp

Perfect for trail running. You'll still need a longer-range one for route finding.


  • Small
  • Light
  • Simple
  • Even, shadow-free light
  • Rechargable!
  • Ideal for running
  • Flashing mode, to make trail running more fun!


  • It doesn't replace your regular long-range light

As fall approaches and nights get longer many say goodbye to trail running and relegate their morning runs to either asphalt (yawn) or a treadmill (sacrilege). 1st world problems at their best. Many runners either quit running in the mornings during the winter or stick to lighted streets.  The struggle is real.

You can use a headlamp but:

  1. Most headlamps eat WAY too many batteries for daily use.
  2. Full power headlamps are overkill for trail running. 

Trail runners need a wide-angle light that reaches to the 20-meter range to keep from rolling an ankle. They also need the light pattern to be even, not a spotlight like we want for route finding on a ridge someplace.  

The Black Diamond Iota does a really nice job of solving these two issues.

IMG_20160930_135434998_HDR.jpgPictorial instructions, 3hr recharge time listed is accurate


Testing Conditions

I wore the Iota from October to late December in temperatures down to zero Fahrenheit and in a lot of misty rain; the kind that makes you run faster to outpace hypothermia. We had our rainiest October on record where I live and I ran with the Iota four days per week. It never leaked or failed. 

I also sleep in my headlamps when I camp so a smaller one like the Iota is nice and doesn’t interfere with my sleep as much.

IMG_20161119_173559710.jpgGreat for short range tasks

IMG_20161001_053438449.jpgCan you see the doggie's collar?


The Iota lists an effective maximum range of 40 meters, which I consider a bit optimistic.  I found it useful to 20m on normal nights and up to 35m in snowy conditions. 

IMG_20161001_052549779.jpgShort range clean beam

IMG_20161001_052853601.jpgSummit the dog (R.I.P.) starting to disappear at the end of the beam


Beam Quality

Remember when LED lamps had that weird, strobe-like light that looked really blue and made the world look off-color? No more! I found the diffused light of the Iota to be very even, with no shadows or strobe-ing. 

The only thing about wearing a lamp co-axial with your eyes is that it can make the ground look flat; like there are no shadows. This can make ankle-twisters blend in with the ground so running in the dark is an acquired skill and probably isn't for everyone. I have personally suffered a season-ending sprain from this so be careful and go slow on unfamiliar terrain. 

IMG_20161119_173524598.jpgMuch better in the snow


Burn Time

I found the lamp to be as long-lasting as advertised and then some. I left it on sitting on a table and, after a day of it still going I just got tired of waiting for it to die and just shut it off. The "possibility of getting lost in the dark with a dead headlamp" score on the Iota is low, which is good. 

Accurate burn times on the box




The Iota advertises being splash-proof and it delivers. The Iota easily stood up to as much rain as I was willing to run in. Obviously, make sure the charging port is closed before you leave the house to keep water out. 

IMG_20161221_104120596.jpgNice and small


Using the Iota for camp chores like cooking on the low setting was nice. I never wished for anything between low or high power but if you did there is an infinite amount of dimming settings between the two modes in case you need that perfect level of brightness for some reason. Toggling from the level you set back to high power is as easy as smacking the Iota on the side; the lamp changes from lower to higher power with a tap. Unfortunately this happens sometimes when you are only trying to angle the beam lower or higher. 

  • The Power Tap feature is kinda cool; one tap makes it switch from high to low to strobe but I never felt like I was in that much of a hurry to fo from high to low beams. 
  • Strobe mode? Cool but no thanks. It's there but I never caught myself saying, "Gee, if only I could only see where I am going every other second."
  • There is also no red/green mode for those tactical types who don't want to lose night sight, leaving them vulnerable to "the enemy," whoever that may be.   

IMG_20161221_104220845.jpgRecharging is so easy


The Iota spent many hours smashed in my pack and never showed any signs of wear at all and never accidentally turned on. The tilt stayed tight and the housing held up very well.

IMG_20161221_104204209_HDR.jpgBig enough button for gloves


I used the single, large button with the gloves I ski in and had no issues. 

IMG_20161221_104300440.jpgIn case you forgot how to wear it :)

IMG_20160930_134841075.jpgThe box, more packaging than it needs IMO

IMG_20160930_135051085.jpgBurn times claimed were accurate

Best For

Trail runners or anyone else who needs a headlamp for up to two hours per day on the reg and hates buying batteries. I really wish a headlamp this small and rechargeable had the power to be my only headlamp but, alas, it is not meant to be.


Update:  In the interest of using things for things they weren't designed for I used the IOTA on my fifth summit of Mount Rainier. I had a long-range headlamp on my rope team in front but, as I was in the rear and the snow increases the effectiveness of ANY lamp, it worked perfectly.  

Good enough in the snow and cold for a Rainier summit

Update 08/2019: My daughter (the one in college) stole it and reports that it still works strong. It's in Puerto Rico now on a mission trip with her I think. Being stolen is probably one of the highest forms of praise a piece of gear can get.   ;)

Source: received for testing via the Trailspace Review Corps (Sample provided by Black Diamond for testing and review)

Good for car camping and home use.


  • Simple
  • Rechargeable
  • Even light coverage


  • Headband adjustment

Update 12/19: I have been using my Iota sporadically for six months now. I have not had any problems. I still am happy with the product. It is a great general use headlamp for light backpacking, car camping, home repairs, night jogs, defined trails, walking the dog, etc. In serious wilderness a different headlamp design would be better. The Iota lacks the punch to see distance.

Original review:

The Iota (150 lumens) seems to be a great basic headlamp for use around the house and car camping. I love that it is rechargeable. I do not have to worry about conserving batteries. It uses the same charger as my cell phone. The headlamp weighs little and is comfortable.

I used the Iota car camping in a campground for a week. The campsite and adjoining sites had electricity and some areas of dim lighting, therefore my eyes never adjusted to true darkness. In this somewhat lit campground environment the Iota output did not seem especially bright. However in true darkness I think the Iota would seem very bright.

Anyway, I could see well enough using the Iota. I was able to comfortably wash dishes, cook, read, clean up the campsite, etc. I did not feel much need for a brighter headlamp. I typically had the brightness setting at 60%.

The Iota light output is even, wide, and short. This is great at a campsite. However, if hiking in true wilderness with undefined trails the Iota would not be ideal. In the wilderness a headlamp with a spot light, more throw and distance, would be better. Around camp the even light output of the Iota is perfect.

The headlamp defaults to 60% output each time it is turned on. This setting can be reprogrammed if needed. The "powertap" side button worked well for me. It cycles the light to max output and back to the previous setting.

The Iota is comfortable to wear. However I found the headband a little annoying. The size adjustment is awkward. The headband did not loosen while wearing, but the headband easily loosens when not in use. So I had to adjust the headband a few times during the week. Also the headband width is smaller than most. Therefore it may not be easy to find a replacement headband in the future.

The aiming hinge does not click and snap as most headlamps do. This makes me wonder if the hinge will loosen over time. But the hinge holds tight at this point, as a nearly new headlamp. The headlamp itself is not heavy and does not need a substantial hinge.

The light output color temperature leans a little blue, like many LEDs. But it qualifies as a white light. It is probably similar to a "daylight color temperature" LED bulb. I found the light color temperature comfortable. However I prefer warm light. The LED lens does not seem to create color diffraction or hot and cold spots.

I did not need to recharge the battery during a week of sporadic use around camp. I timed the battery depletion at home. The battery lasted six hours at the 60% brightness setting.

I did not use the Iota in rain. It appears to be rain resistant. The Iota is rated IPX4. A rubber plug for the USB port needs to be pressed shut for rain resistance. It looks like the plug may tear off after years of use.

The Iota power switch has a lock function. It has an infinite dimmer adjustment.

The lithium ion battery is not accessible or replaceable. Disposable batteries cannot be used. Therefore the Iota headlamp is not suited for infrequent use or indefinite storage as an emergency light. The USB charging port is micro-USB, not USB-C.

The Iota's written instructions are horrendous. Look for product videos online instead.

Overall I am happy with my Iota. I like the simplicity. I love the rechargeable battery. The Iota is now my first headlamp choice for car camping. I even bought one as a gift for a friend.


I have only used the Iota on one trip. I used it at a campground, car camping.

I have owned several high quality headlamps, spanning early 2000's LEDs until now. My newest models are the Black Diamond Iota and the Black Diamond Spot 325.

Source: bought it new
Price Paid: $22 on clearance

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Price Historic Range: $18.73-$39.95
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