Shouldn't matter all too much, but put it on the inside facing the LED. That way it will remain clean and free of wear. The AR lenses on KD is coated on both sides btw.
Thanks for the clarification and the link!
Interesting notice, I was forced to take the KD route because only them have the 19 mm coated or not for my P10 , sadly I can not try the before and after test cause the broken 'before'.
After reading this post I ordered one 18 mm to try that test in one of the Hugsby P31. Too bad the only supplier of 23 mm ones, for the RC-G2 , is that guy mentioned above who apparently don't take PP and the wording of his contact information seem very unfriendly.
After all those praises on coated lenses I officially made the first order of year 2011. I had many coated filters on my cameras and I know how they work on contrast. I guess they can really change the results.
Four 28mm (for L2p, L2r, L2 and KD R7), two 38mm (for C8 and Eastward), one 52mm (TR1200), one 18mm and one 19mm for various EDC lights. I guess I'll wait a long time for KD to collect all these items together.
Pity, all of my multicoated camera filters start from 49mm. I now think I could have taken a 52mm filter and use the glass. Maybe it's the time I should invest in bigger lights :)
It is fascinating how well this thered developed. Lenses were hardly ever been discussed. One can never learn enough it seems. Unitill few days ago i did not realize the lenses potential alone. It seems that is possible to achieve better results with lens change than emitter swap alone if not drastical emitter change.
KD should thank me for the unusual number of lens sales these days. XD
My order changed from "backordered" to "pending" today, which I am hoping is a good thing. I hope these work out. I guess I could have tried at least doing a comparison of a flashlight with a glass lens and without to see how much difference that makes before ordering the coated lenses. That would have given me some idea of how much I'm losing through the glass now.
Changing from a plain glass lens to an AR coated one should increase the "out the front" output by around 7% (plain glass reflects ~8% and AR coated glass reflects ~1%). There could also be other lens related factors affecting the output, YMMV. Still, it is a pretty cheap and easy way to increase output.
Can you see the 7% increase?
The best way to see the increase is to test it:
1) Try the light without a Lens.
2) Try the light with AR Glass Lens.
3) Try the light with Plain Glass Lens.
What difference do you see?
Tested with my C2 XM-L and a cheap DX luxmeter:
Without: 14500 lux @ 1m
AR: 14300 lux @ 1m
Plain: 13300 lux @ 1m
Both lenses were cleaned before the test.
The difference is visible if you alternate between the lenses. It _is_ a visible difference and it is a good improvement, it just isn't a huge difference. Note that the lenses were cleaned before the test, if you get more than a 7%-ish gain from swapping lenses then the original lens was probably not all that clean or there could be other variables involved.
Thank you for running the test, Spambot. That's good info...but now I gotta get some coated lenses :)
It's good to see some actual numbers and I'm glad they seem to agree with what others have said. My order at KD is showing as "pending-packed" so it will probably ship today or tomorrow. Now that I think about it, I should have probably gotten the cheaper ones. Even if there is a difference and the more expensive ones are better, what are the odds they are going to send me those? Still, not a big price difference either way.
"Even if there is a difference and the more expensive ones are better, what are the odds they are going to send me those"
That was the only reasoning behind my purchase of the cheaper ones.
Am I correct to assume that http://www.kaidomain.com/ProductDetails.aspx?ProductId=1766 and/or http://www.kaidomain.com/ProductDetails.aspx?ProductId=9064 are the same "coated glass lens" that come installed on the UltraFire WF-501B (DX sku.39359) and UltraFire WF-502B (DX sku.35076)?
Size wise yes, coating nope. These are actually at least 20x more expensive than plain glass (manufacturing wise).
I do not own the lights in question, but I think that it is safe to assume, based on previous experiences, that DX specs for those lights, especially the "coated glass lens" part, is a fair bit off. If those lenses really are coated in something, then my first guess would be the usual "foggy lens" coating and not a real AR coating.
Maybe DX specs mean "finger print coated"? ;)
Thanks for the good laugh! Still giggling. XD
Just got three of the KD lenses. Time for a test. Charged a cell, put it into the light with the XM-L dropin in it. Got 3080 lux on the lightbox - around 550 lumens. Changed the lens for a KD coated one, topped off the cell to the same voltage and got 3840 lux/690 lumens, a dramatic increase. OK, cleaning the original lens might well have made a difference, but I was surprised by how huge a difference the new glass made.
These are Multi-Layer Coated HD Flashlight Lens according to the bit of paper KD put in with the order. KD is being horribly slow just now so can't get the link but they are 28mm diameter and 2mm thick and cost $2.99.
At last!
That's a 25% increase! Could you try cleaning the plain glass lens and seeing if that makes a difference? Is it possible to take the lens out entirely and test?
That's what I was thinking too. No lens is quickest so, 4700lux/850 lumens with no head at all, just the dropin wedged into the throat of the light body. Off to wash the old lens.