Ok guys, so just when I thought I’d leave this light aside for a while another package arrived and I had to get stuck in again. Only a small mod this time but it’s probably put the biggest smile on my face so far.
I decided to take a little gamble a while back before I had the light and ordered a 73mm lens from flashlightlens.com thinking if I was lucky it might just fit this light.
This is a multicoated Acrylic (yuck plastic! :P) lens but the specs are pretty damn convincing so I thought I’d give it a go.
I couldn’t find any other glass AR lenses of the right size and was pretty keen to try this type of material and give the coating a closer look. I mean I’ve been wearing AR coated acrylic glasses for years and the coating can take a beating, so how bad can it be.
So anyway I got this lens today and replaced the stock uncoated glass one tonight, thankfully it’s a perfect fit. Being Acrylic a bit of sanding down wouldn’t have been out of the question but it fitted right in…and…all I can say is WOW! This is a very impressive piece of kit, the coating is incredibly anti reflective totally on par with the coating on some very high quality acrylic lenses in my eyeglasses.
Comparing side by side with my other AR coated glass flashlight lenses, one from cnqualitygoods and another in the BTU shocker (different coatings with BTU lens being superior) this acrylic lens puts both to shame. It’s also quite stunning with it’s reddish sheen.
Here cnqualitygoods AR lens in HD2010 (Top) and Bighead Acrylic below. I may have overexposed just a tad but it should be obvious that the Acrylic lens reflects much less of the filament bulbs intensity, the difference is even more apparent in person.
The HD2010 lens isn’t the best AR coating I’ve see but it still puts an uncoated glass lens in it’s place.
The Acrylic lens is really spectacular in this regard, most dimmer light sources just don’t register in the lens at all so it gives a spectacularly unhindered view into the reflector.
With the light on there are clear positives but also one negative point to report.
The biggest benefit I noticed right away with this lens is far less prominent beam artifacts due to internal reflections. The main one that plagued this light is a fairly noticeable ring artefact around the central hotspot just past the fringes of the corona. I figured this might be due to rogue photons bouncing off the uncoated glass lens and that seemed to be the case since the AR coating on this new lens has almost completely removed it. And what little there is left is much softer and really dim so it’s hard to spot now, BIG improvement.
There is also less light spilling out of the sides of the beam close to the reflector, this used to be quite obvious in a bright ring projected at around 120degress all around and now it’s very faint and tinted slightly red.
Note the reddish sidespill compared with the very blue sidespill of the cnqualitygoods lens. Both look pretty cool and distinctive and on the bighead that ring is massively dimmer than it was before.
On the downside.
Looking at the light when it’s on, the lens is very slightly more “milky” than a perfectly clean glass lens. This is probably just the material itself absorbing and scattering a small amount of the light as it passes through but it’s really no worse than the general standard of “clean” glass lenses we tend to get. Even if there is a tiny bit of oil or impurities on or in the glass it starts looking very similar.
It’s just a shame because this is the only thing not truly spectacular about the lens and it would be amazing if it was as clear when on as it is when off…but it seems there’s always a tradeoff.
In any case going by the specs for this lens material and the 97% transmission figure I’d be happy to say that the light being lost through internal reflections on the stock lens is probably far more significant than what is being swallowed up by this one because of it’s material composition. That combined with the much cleaner beam profile and just damn gorgeous appearance I’m giving this lens a full thumbs up!
I’ll just file this under flashlight porn shall I?
A bit of an unknown is how durable this coating will be, it’s certainly more prone to “blueing” when touched with anything oily (similar to a photographic lens coating) and is probably less hard wearing than an equivalent glass coating but this remains to be seen. I’ll treat it with a bit more care than I normally would but hopefully it holds up well in general use.
If someone finds a quality glass AR lens for this light then that may still be the better option, but overall I’m really pleased with this upgrade to my light.