Does Jetbeam use real sapphire crystal lens?

If they are indeed real sapphire crystal, scratching them with your keys shouldn't leave a mark. Anyone care to try theirs out?

High density glasses are also scratch proof. Along with many other polyethylene compounds. Like that iphone screen protector, just a piece of plastic, but virtually unscratchable.

But they could also have just used a thin "coating" of sapphire.

I'm not sure if there's an official definition for "scratch proof". But here we're talking about hardness 9 on the Mohs scale, just next to diamond's 10.

If you look at the Jetbeam window closely, it is very slightly cloudy. Not dirty but not crystal clear like normal glass. I understand there is some transmission loss through the crystal lenses but improved durability.

jr/

richardcpf said:

High density glasses are also scratch proof. Along with many other polyethylene compounds. Like that iphone screen protector, just a piece of plastic, but virtually unscratchable.

But they could also have just used a thin "coating" of sapphire.

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Actually it might be a good idea to use an Iphone screen protector as the front layer of these cheap lights from DX to make them scratch proof.

donghui said:

Actually it might be a good idea to use an Iphone screen protector as the front layer of these cheap lights from DX to make them scratch proof.

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Now here is an idea that I can use on all my DX lights. Thanks.

donghui said:

Actually it might be a good idea to use an Iphone screen protector as the front layer of these cheap lights from DX to make them scratch proof.

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in fact most of watch lens use crystal lenses because it's unscratchable.

simple said:

Jetbeam has always claimed that their flashlights use sapphire crystal lenses. But I just heard that after their first batches made in 2004, they have stopped using sapphire crystal. What they've been using is a kind of optical glass used for cheap watches.

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OK，so where did you get these informations?"I just heard" means nothing.What we need is a formal acclamation from Jetbeam.

simple said:

Jetbeam has always claimed that their flashlights use sapphire crystal lenses. But I just heard that after their first batches made in 2004, they have stopped using sapphire crystal. What they've been using is a kind of optical glass used for cheap watches.

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Hmm....they're still advertising sapphire crystal lenses....:thinking: I'd be surprised if what you heard was correct.

Slightly off topic, but...
Are Jetbeam's lens AR coated?

I'm asking because i couldn't see a hint of it yesterday when i was cleaning the lens, no matter how i'd turn it and light it. It either doesn't have an AR coating or it's coated on both sides and it's not a "multi-coat". Both sides look identical and don't show the usual tint or split highlights of a multi-coated AR layer.

sapphire crystal lens cost no more than 5$.

I'm always wondering how so many posts can include so much ...

The simple question was: "Does Jetbeam use real sapphire crystal lens?"

Answer: Jetbeam say they use real sapphire crystal lens.
I just tested the lens of my Jet III pro I.B.S and i had no chance to scratch it with a hardened knife blade (which has about 60 - 61 HRC).
So, maybe (or perhaps for sure) they use real sapphire crystal.

Question answered or not?
Nothing as simple as that...

They use synthetic sapphire.. Just as strong but doesn't have the slight amounts of other minerals that natural ones do.

Sapphire crystal passes about 93% of the light it comes in contact with. When I change out a Shoppe Aleph lens (sapphire crystal) with a UCL, I measure about 6%-7% gain in overall lux. I've changed out my MKIIx and MKI I.B.S. lenses with UCL and there was no change in output.

Perhaps synthetic doesn't hold back as much light as real sapphire crystal.

McGizmo uses sapphire crystrals and he speaks about a transimssion loss of roughly 10-12% (compared to no lesn at all, that is), and this is with a coating on the inner side of the lens.
bernie

Nake said:

Sapphire crystal passes about 93% of the light it comes in contact with. When I change out a Shoppe Aleph lens (sapphire crystal) with a UCL, I measure about 6%-7% gain in overall lux. I've changed out my MKIIx and MKI I.B.S. lenses with UCL and there was not change in output.

Perhaps synthetic doesn't hold back as much light as real sapphire crystal.

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All crystals on both watches and flashlights are of synthetic origin. If you're getting a more noticeable difference by switching out sapphire on one light over another you can probably attribute it to coating technology.

The UCL you mention, would it be worthwhile putting into less expensive lights like Fenix, Nitecore and Jetbeam?

kaichu dento said:

The UCL you mention, would it be worthwhile putting into less expensive lights like Fenix, Nitecore and Jetbeam?

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Fenix and Jetbeam, no. Haven't tested a Nitecore. Most of the gains I've seen were with cheaper lights except for the Shoppe lens and that has a coating. Must be a dense glass. I did see a gain with the iTP9. Haven't found any UCL for Fenix (19mm), but I've put an 18mm in just for testing.

A) Put the Jetbeam lens in a cup. Fill the cup with water. Weigh.

B) Remove the lens. Weigh.

C) Fill the cup with water. Weigh.

specific gravity = (A-B)/(C-B)

kris994 said:

They use synthetic sapphire.. Just as strong but doesn't have the slight amounts of other minerals that natural ones do.

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Aye Cap'n. Transparent aluminum (oxide)! :naughty: