I got an email from Shoei last fall: Would I like to test-run the company’s new CNS-2 photochromatic helmet shield? Er, yes, but I don’t have a Shoei helmet to test it on. No problem, the rep said, we can send one along. A few weeks later, a nice man in a brown truck dropped off the helmet and visor, and I put them together.

Now that the winter weather is clearing up, I’ve had more opportunity to test the shield, enough to get a good idea of what it’s all about.

The photochromatic shield is an expensive upgrade, but it offers excellent optical clarity while reducing glare. Photo: Shoei

What’s a photochromatic shield?

Full-face motorcycle helmets, as well as modular and most adventure-style helmets, all come with a clear face shield for night riding. But what if you want a bit of shade? Some riders go with a tinted face shield, but that’s no good at night. You could bring a spare face shield, but then you’ve got to find a place to store it on the bike without scratching it, and you’ve got to swap it out mid-ride, etc., etc. It’s a pain in the butt. Or you could get a helmet with a drop-down sun shield, but then you get more visual distortion.

What you want is a face shield that’s dark in the daytime, and clear in the nighttime. That’s where photochromatic technology comes in.

According to Wikipedia, that faultless source of reliable information, “A photochromic lens is an optical lens that darkens on exposure to light of sufficiently high frequency, most commonly ultraviolet (UV) radiation. In the absence of activating light, the lenses return to their clear state.” In the case of a photochromatic face shield, when sunlight shines on it, it automatically darkens. When the sunlight goes away, the face shield material returns to its normal transparency.

How does it all work? Once again, according to Wikipedia:

Plastic photochromic lenses use organic photochromic molecules (for example oxazines and naphthopyrans) to achieve the reversible darkening effect. These lenses darken when exposed to ultraviolet light of the intensity present in sunlight, but not in artificial light. In the presence of UV-A light (wavelengths of 320–400 nm), electrons from the glass combine with the colorless silver cations to form elemental silver. Because elemental silver is visible, the lenses appear darker.

In other words: There are fancy-pants molecules in the plastic that turn dark, thanks to a chemical reaction when exposed to UV light.

The photochromatic shield’s opacity depends on how much light it’s exposed to. Photo: Shoei

How does the Shoei Hornet X2 CNS-2 photochromatic shield work?

The Hornet comes with a clear shield; the photochromatic shield is a $209 add-on accessory. You can find it here on the Shoei website, or search Google/Yahoo/DuckDuckGO for “CNS-2 Transitions Photochromic Pinlock Shield,” and you can find other sellers’ pricing.

The CNS-2 shield arrives in a plastic baggie, to prevent scratching. It’s not hard to install; the Shoei’s visor unscrews by hand. From there, there’s a catch on the helmet’s stock face shield, on the pivot point at each side. Many manufacturers use this arrangement, and I’ve always found it a bit finicky, but not too bad. Certainly easier than the Arai face shield retention system, although not as idiot-proof as the crude screws on a Zox helmet.

Once it’s installed, there’s nothing else to do. No batteries to change, thankfully, unlike pretty much every other moto gadget on the market. You just go for a ride, and the face shield takes care of the rest.

I was actually surprised, the first time I used the CNS-2 photochromatic shield—the transition really is smooth, just like Shoei says. You go from a bright, sun-blaring day to a nice shady view without even really noticing at first. Riding along, I felt like the sun was sinking in the sky, the shield cut that much brightness—but the sun was still high up.

The shield does an excellent job of darkening the rider’s entire field of view, unlike sunglasses, which always let light in the sides. There’s no sunglass arms digging into the sides of your head. And, because the CNS-2 shield is a single pane, you don’t get the distorted vision you sometimes get from sunglasses or a drop-down internal sun visor. The world looks exactly like it should, only darker. Which is exactly what most people want.

If you’re the type of person who’s annoyed by visual distortion – and I certainly am – then this is a great upgrade to your helmet.

Installation is simple. Just pop out the old face shield, install the new one.

Potential issues

So is this going to be for everyone, in every situation? I don’t think so.

First off, this isn’t a cheap face shield, and everyone knows that it’s easy to scratch a helmet shield. If you’re riding through a lot of dust, or wet muck – slogging up the Dempster, or maybe the Trans-Lab – then you’re going to cover your visor in grit. You might be able to clean that off without scratching, or you might not, depending on condition. If you need visibility right now, you need visibility right now, and you’ll wipe your filthy glove across the face shield, scratching your photochromatic shield. This is much less likely to be a problem if you’re just on the street, or riding offroad in non-dusty conditions, or maybe you flip up your face shield and use goggles while you’re offroad.

Another potential issue: While riding with the photochromatic shield as the sun dropped behind trees, there were times I wished for less shading as I rode through shadows. The shield doesn’t change its tint instantaneously. If you’re riding on a bright sunny day and head into a tunnel, covered bridge or underground garage, your shield won’t lighten right away. You might have to flip it up, if you’re riding into deep darkness. The instruction manual warns riders about this, and it’s not a big deal, just something to be aware of.


If you’re putting in serious mileage as a commuter or long-distance tourer, I think you’ll love the shield, as long as you don’t mind the expense. The MSRP is really the only reason I wouldn’t own one of these for every helmet. Hopefully, the price will come down a bit in the future, putting this in the reach of more riders.

If you’re wondering about the Shoei Hornet X2 helmet itself, you can find @Butterqwup ‘s review here. She summarized her review by saying “It’s one of the most comfortable helmets I’ve ever worn. It’s quiet and flows air quite well. The field of vision is large and the peak provides only minimal buffeting during head checks; at all other times, it is very stable.” I found the same, My only issue is that I ordered a size M, which was too small. I ordered smaller internal padding, which got the fit to a point I could wear it. The lesson here is, try your helmet on before ordering online—this is why you should order through your local bike shop.


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