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Olight has been a leader in the high-end flashlight industry for quite some time now, and they are continuing to improve their models in every category of use. Today, they're pushing forward in the headlamp realm with the H25 Wave, a hands-free headlamp with the ability to pump out 750-800 lumens for over 5 hours...
Thanks to Olight and GoingGear for providing the H25 for review.
I'll be reviewing the H25 in two sections: first, I'll discuss the light objectively (the facts about the light itself), then I'll discuss the light subjectively (my impressions about the light's performance when used for specific applications). If you have any other specific applications you'd like the light tested for, let me know and I'll see what I can do.
Video Review
Below is a video review of the H25. Due to my old image hosting site closing down, I've got new restrictions on image uploads and have replaced the "Construction" section of my reviews with a more detailed video review.
This video is available in 1080p HD, but defaults to a lower quality. To select the playback quality click the settings button (looks like a gear) after you've started the video.
Objective
Manufacturer's Specifications
Price: 120 USD
Product Manual
Dimensions
Plus, here's a few shots with some good detail.
User Interface
To see the UI in action, be sure to watch the video above.
The H25 is controlled either by the switch on top of the light, or by an infrared proximity detector, and has three brightness modes. The infrared detector is operated by waving your hand at a medium speed at a distance between about 1-12 inches in front of the head. The infrared detector function can be turned on or off by holding down the switch for about three seconds while the light is on (a quick flicker will indicate that it has been switched on or off).
Clicking the switch cycles the light through the modes High -> Medium -> Low -> Off. Waving your hand in front of the light turns it on or off, unless you have deactivated that function. You cannot change the output using the wave, it only turns the light on or off in the last output mode you used.
Action Shots
You can click on any of these shots to see them full size.
Light in Hand
Light on Head
MugShot
BeamSlice
White Wall
ISO 100, f/3.5, 1/20"
Indoor Shots
ISO 100, f/3.5, 1"
Outdoor Shots
ISO 100, f/3.5, 2.5"
Performance
Submersion: The H25 is rated IPX-6 ("heavy jets" of water, not submersion), so I fixed it near the shower head and let the shower run on it for about half an hour, clicking the switch a few times during that period. I could find no evidence of water entering or damaging the light or battery pack.
Heat: On High, the H25 gets hot after about an hour of use when not moving around, however being in a windy environment or moving around with it makes a big difference. Having such a small mass and possibly poor thermal connection to your body (if you're wearing a hat or hair) makes me concerned about heat dissipation away from the emitter if you use High for long periods of time.
PWM: I did not detect pulse width modulation on any mode of the H25.
Drop: I dropped the H25 with battery pack from about a meter onto various surfaces (including grass, carpet, dirt, and hard wood), and found no cosmetic or functional damage.
Reverse Polarity Protection: Not an issue, included battery pack only connects in the correct direction.
Over-Discharge Protection: I can't find mention of any over-discharge protection built in to the battery pack, though on my runtime tests the light did cut out abruptly, so that seems to point to some sort of cutoff voltage built in to either the pack or the cells. You can use the voltage indication LED, which lights up green, yellow, or red when you press the button on the battery pack. The red indicates <20% charge remaining.
Spectral Analysis
All light that we see as white is actually made up of several different colors put together. The relative intensities of the different colors in the mix are what determine the tint of the white we see. For example, cool white LED's have a lot of blue, and warm white LED's have more red or yellow. This measurement was done on a home made spectrometer. The plot below the picture is corrected for the spectral sensitivity of the human eye. Note: the peak in the 900nm region doesn't really exist, it's a piece of the second-order spectrum that's showing up here because of the high intensity of the light source.
Output and Runtime
ANSI FL-1 runtime ratings are the time it takes for a light to fall to 10% of it's original output (counting from 30 seconds after turning the light on).
The vertical axis of the graphs below represents a relative brightness measurement using a home made light box. The horizontal axis is time in hours:minutes:seconds. Runtimes are stated in hours:minutes:seconds. These graphs may be truncated to show detail.
Mode Comparison
High
Throwing Distance
ANSI FL-1 standard for stating a light's throwing distance is the distance at which the peak beam intensity (usually at the center of the beam) is 0.25 lux. I calculate throwing distance and candela (lux at 1 meter) by measuring peak beam intensity at five different distances and using the formula lux*distance^2=constant.
Note: A calibration factor of ~6.88% has been added into my throw measurements starting on 9.11.14. To compare the throw of a light I reviewed previous to that date, multiply the candela value by 1.0688 to get the corrected value.
Subjective Review
Quick break down:
+ Hands-free
+ High capacity battery pack = long runtimes
+ Neutral tint
+ Surprisingly good throw
+ Lightweight head section
+ Excellent regulation
+ Battery indicator light
+ Can deactivate hands-free use
+ Simple UI
+ Charge devices with battery pack
+ Adjustable angle
+ Comfortable headband
- Bulky battery pack
- Cord a bit short
- Cord disconnects too easily
- Accidental hands-free activation or deactivation
I've never gotten the chance to use an infrared-activated flashlight before, but I have to say this one was a lot of fun. I've done a bit of research on the older H15, and it looks like Olight has made some good upgrades in the design since then. Most notably, aside from the significant output increase, they've changed the power source from 4xAAA to a (2s2p or 2p2s) 4x18650 li-ion battery back with the batteries already built-in to the pack, they've covered the IR emitters with visible-opaque plastic (similar to a TV remote), and they've lengthened the cord so that the battery pack can ride on a belt. Unfortunately, they took away the flip-down diffuser, which I consider a loss. Overall though, the H25 is a much more powerful beast than the H15 was.
First, let's talk about the hands-free feature, which is probably the big item for this light. On either side of the main emitter sit an infrared emitter/detector pair, which are used to turn the light on and off without touching it (the manual is a bit unclear on this point, bus as far as I can tell you cannot change modes with the hands-free function). Presumably, the emitters are constantly putting out some infrared light, and when you pass your hand in front of the light, some of that infrared light is reflected off you hand and back into the detectors. There is some sort of programming that determines what signal from the detector represents a true "wave event", because simply holding your hand or some other object in steadily in front of the light does not turn the light on or off. So, a brief pulse from the detector of certain approximate length and magnitude has been determined to be associated with waving a hand in front of the light, and when the detector sends this signal then the light will turn on or off. I'm glad it's been designed this way, otherwise the hands-free function would be extremely erratic, as the detector must be getting variable infrared signals quite often depending on the environment. From my testing, I've found the hands-free function responds to a wave of the hand at distances from about 1 inch to about 12 inches, and at certain moderate speeds. I don't have any simple way of measuring the speed necessary, but it is pretty comfortable for a hand wave in front of my head, and if you get one of these it just takes a bit of practice to train yourself for the right distance and speed. At first it can be a bit difficult to get the wave right, but after practicing it for about 15 minutes I was able to do it consistently, and now when I take it on a bike ride I can do the wave successfully without any conscious effort or distraction from what I'm focusing on. The downside to this is that the light's wave-event filtering algorithm isn't quite perfect, as when I am using the headlamp in close quarters I've had several accidental activations or deactivations. For example, I might reach above my head to grab something, or pull my backpack off my back, walk too close to a wall or doorway, bend over near a chair or table, etc. I can't think of any way the lamp could have been designed differently to distinguish between a hand and some other object giving a similar pulse, so I've decided you just have to turn off the hands-free function if you're going to be working in close quarters with other objects. Additionally, I have to remember to turn off the hands-free function when I'm done using the light for the night, so a false wave event doesn't accidentally turn it back on.
Next, I'll talk about the performance. My favorite thing here is that I have a solid 5 hours on High before I run out of battery power. The regulation is excellent, but I do wish there was some period of low output at the end before the light just turns off. You can use the battery pack as an approximate voltage indicator, but you have to actively take out the pack, open up the flap, and press the button to see what color it lights up. Even if it lit up on it's own, I usually have the battery pack on my hip or backpack, so it takes conscious effort to check the voltage, which decreases it's value as a warning. It's nice to have that feature of being able to check the battery voltage, but on a light like this I would also really like some warning from the main beam before it just turns off. Other than that, I find the modes to be well spaced, and the beam pattern is much better than I expected from such a small reflector. The throw on it is actually pretty impressive, one of the best throwing headlamps I've seen, with a smooth transition into a wide spill zone. I've found this great for bike riding--I have a floody light mounted on my bike, and with this throwy headlamp on my head I can see pretty much anything I like. The neutral tint of the beam is great too, and I find it very helpful in distinguishing colors in the night.
Now, let's look at the battery pack. It's great that it has a high capacity, and using the 2p2s or 2s2p configuration (I'm not sure which they did without opening it up) means it gets up above the 5V line for USB charging of other devices. The trade-off is, it's much bulkier that single-cell headlamps with no battery pack, or even other multi-cell lights with smaller packs that can sit on the back of the headband. In using this light, I've found this is a very significant factor--it takes time to position the battery pack, position the cord, connect them so they won't come undone, etc. For me, I'm pretty tall, so the cord isn't quite long enough to run from my head to my pocket. It will run to my belt though, but with not much slack left over. In addition, the connection between the pack and the headlamp cords isn't very strong and doesn't have any threads or clasps, so it will slip out if you pull on the cords much. I can see some situations where a quick-release cord might be advantageous, but for me what it mostly means is an extra thing to worry about. So, all together the H25 isn't just a headlamp I can grab on throw on for some quick use, it takes some time and a bit of thought. However, as I mentioned, it can run 5 hours on High, or obviously more on lower settings, and it's performance is excellent and the wave feature very handy for many activities, so if I'm going to be using it for very long it's worth the time for me to get it all situated and hooked up properly. This means I find the H25 useful for longer time period tasks, but not worth the effort for short tasks. So, if you're looking into this light, keep in mind what you'll want to be using it for, as it likely won't replace a small single-cell headlamp for you, but is great if you need something with more power.
Those are the main points, but the little things here look good too. Being able to have 5200 mAh at my disposal to charge USB devices is a huge benefit, and makes even the battery back worth carrying around on it's own (I can charge my phone about 2.5 times with this pack, and I calculate nearly 3 charges from it if you have an iPhone). I like how lightweight the headlamp is without the need to carry the batteries on your head, this means I can wear it the full 5 hours or more without any discomfort. The headband is fully adjustable, and fits just fine on big heads like mine or small ones like my sons'. The over-the head strap increases the comfort--I'm not a fan of headbands that just go around the side, you have to make them overly tight to keep the light in place. The angle of the head is adjustable, but only in the downward direction, so I generally mount the base of the headlamp fairly high on my head, then adjust it to point downward a bit so I have wiggle room in both directions. The adjustability is notched, so you don't have to worry about it slipping as you move around over time:
Overall, the H25 Wave is an excellent headlamp with very few negatives. If you're looking for lots of output over a long time, and are willing to carry the extra battery bulk, the battery pack is worth it and has the great bonus of charging USB devices. The beam is neutral and has better throw than most headlamps, and the hands-free wave function means this light has some unique usefulness in many tasks. If this is what you're looking for in a headlamp, I don't think you'll find it anywhere else!
Long Term Impressions
I'll fill this part in after carrying the light for a while. If nothing get's added here, either I find nothing else worth noting about the light, or I end up not using it often.
UPDATE 10.10.14
I did a bit of investigation after some questions were raised in the discussion:
1. The body does seem to be made of metal. However, it looked plastic to me at first glance for a couple of reasons. First, the whole front of the light has some sort of plastic cover, to which the IR transparent / VIS opaque plastic is fixed It pulls up a bit at a tab on the bottom, but seems to be glued to the face of the light. Here you can see my tweezers under it:
click to enlargeSecond, on the back of the light (not covered by the plastic faceplate), the metal body is coated with something that seems a cross between HA coating and plasti-dip (if you're familiar with that). It's thicker than HA coating and not quite as tough, but thinner than plasti-dip and tougher. Here you can kind of see a small scratch I made in it, revealing the metal underneath (on the back corner of the light, just left of the picture's center):
click to enlargeI apologize for the poor photo quality, all I had handy was my phone.
So, yes, a metal body underneath.
2. Yes, I wasn't pushing the cord connection together hard enough. There's a catch point that requires quite a bit of push to get past, but once you get it connected all the way the connection is very firm. This is a huge relief to me, because the flimsy connection I had previously was becoming a source of endless grief. When done properly, the connection is plenty strong to hold itself together for pretty much anything but intentional disconnection.
I'll be posting these updates to the "Long Term" section above, and also add a note in the video review.
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