Polycarbonate Lens? Why call it a lens at all?

[yaesumofo]

Call me crazy but i prefer some form of glass or crystalline "lens" on my flashlights.
I recently received a NocaTac 120 P flashlight.
I notice that this flashlight is a very high quality piece.
I wonder if the choice of a Polycarbonate Lens was to make the light cheaper or was it part of the design spec calling for a lens that will not shatter under all but the most extreme situations.

Does anybody have any insight on this? McGizmo uses Sapphire. Mr Bulk prefers a UCL. No other custom flashlight maker that I know of chooses the
Polycarbonate Lens.
Some how I doubt that NovaTac choose the
Polycarbonate Lens just to make the light a little cheaper. The
Polycarbonate Lens that is stock on the NovaTac flashlights is a top of the line "lens". it is anti reflective coated and is very clear.
All of that being said I still went ahead and ordered some new "lenses" and installed a UCL in my NovaTac 120P. I like the results.

I have no doubt the UCL will work just fine as a drop in replacement of the
Polycarbonate Lens.

One thing I have a problem calling this part a lens. By definition it is not a lens.
(lensplay_w("L0119900") (l

nz) n. pl. lens·es 1. A ground or molded piece of glass, plastic, or other transparent material with opposite surfaces either or both of which are curved, by means of which light rays are refracted so that they converge or diverge to form an image.
2. A combination of two or more such pieces, sometimes with other optical devices such as prisms, used to form an image for viewing or photographing. Also called compound lens.
3. A device that causes radiation other than light to converge or diverge by an action analogous to that of an optical lens.
4. A transparent, biconvex body of the eye between the iris and the vitreous humor that focuses light rays entering through the pupil to form an image on the retina.

)

Why is it called a Lens when used in flashlights?
It is a front glass. It's job is maintaining a seal against water and to protect the emitter reflector optic from dust and debris. It is generally not an optical component or part of a compound lens of any type.
I know there are some people working with optics and lenses. Generally the front glass does't not fall into this category.

What do you guys think?
Yaesumofo

 

[LukeA]

deleted as per request

 

[mmmflashlights]

I recently received a NocaTac 120 P flashlight.
I notice that this flashlight is a very high quality piece.
I wonder if the choice of a Polycarbonate Lens was to make the light cheaper or was it part of the design spec calling for a lens that will not shatter under all but the most extreme situations.

I was just looking at the specs for this light earlier today and noticed it used a 'plastic' lens. Considering the cost and overall quality of the light, I think that you answered your own question as to why it is not glass - to prevent shattering in tough conditions, not to save money. If they can make it optically very clear and neutral, put a good anti-reflective coating and put an anti-scratch coating on plastic, I'm all for it, but that's asking quite a bit. Regarding why it is called a lens, yes it might be a little misleading. A lens is more typically thought of as an optic that changes the focus of the light going through it, but these are more of a protective 'lens' or 'filter'.

 

[Oddjob]

I agree with mmmflashlight. As stated, the polycarbonate "lens" was used for durability. At the SHOT show an HDS was pummeled by being thrown at a concrete wall over 200 times and it still functioned. It had a polycarbonte "lens" that reamined intact where a UCL would probably have shattered after that kind of abuse.

 

[greenlight]

I prefer to call it a window. Even my non-flashaholic friends get that one.

 

[Derek Dean]

I'm curious yaesumofo, did you notice a difference when you changed to the UCL protective cover? So far I'm very happy with the polycarbonate cover and can only see replacing it if I feel that it is reducing the light output by an unacceptable level.

By the way, I certainly don't think you are 'crazy' for wanting a super-clear glass cover. As a photographer I'm always looking for the best 'glass'.

 

[yaesumofo]

I changed the polycarb lens out for a UCL from flashlightlens.com
The switch was easy and the current UCL is a drop in replacment.
IMHO the UCL is clearer. My main reason for the switch is that I do like the front galss to be clean and free of dust. And I like the higher light transmission numbers a UCL offers. If you use your t-shirt to clean the window as I do the polycarb will devolop scratches. Over time they begin to look terrible(just look at your old maglight) and will over tiime effect the quality of the beam.
The UCL has a anti reflective surface just as the polcarb unit does. So What am I giving up? I suppose that I loose the super strength and anti shatter features of the Polycarb unit. What do I gain? I gain a "lens" with a higher transmission of light..that translates to more photons exiting the front. I want as much light as possible when I need it. The way I use my flashlight I have no fear that my novatac will never be subjected to the kind of forces where a polycarbonite lens will be advantagous.
BTW I have done the same mod to all of my HDS EDC's with no problems.
Yaesumofo

I'm curious yaesumofo, did you notice a difference when you changed to the UCL protective cover? So far I'm very happy with the polycarbonate cover and can only see replacing it if I feel that it is reducing the light output by an unacceptable level.

By the way, I certainly don't think you are 'crazy' for wanting a super-clear glass cover. As a photographer I'm always looking for the best 'glass'.

 

[FASTCAR]

I think it was to cut cost.

 

[ensile]

if you're someone who drops his light often, or is susceptible to impact, keep the polycarb lense, for torch whores, the sapphire, "piece of mind" will be the replacement.

anyone who is confused, dw. It was designed with a polycarb window, i don't see, with the depth of it that it will be scratched easily, maybe if some keys were to angle up and jam directly onto it. Don't carry it with some ******* keys.

 

[SunnyQueensland]

Can someone help me with what size UCL window I need for my Novatac (it has not arrived yet) oh and if I can push it, what size is the o-ring as well?
Thanks

 

[gunga]

Also, what is the cost of a replacement lense?

IS UCL considered the best choice?

 

[woodrow]

I think it depends on what the light is used for. I would rather have a "plastic" lens in a dive light for fear of breakage. Also, the new Pelican 7060 has a plastic lens and it was a decently expensive light. Both types have advantages and disadvantes....not just cost.

 

[Nake]

Can someone help me with what size UCL window I need for my Novatac (it has not arrived yet) oh and if I can push it, what size is the o-ring as well?
Thanks

Flashlightlens.com is where I got mine. I ordered the ones listed for the HDS EDC. http://www.flashlightlens.com/appchart.htm My lightbox shows an increase of 400 lux with the glass lens over the plastic one.
I measure the O-ring OD to be 22.5mm.

 

[Bullzeyebill]

What we do not often know about plastic lenses is what the composition of the plastic is. I am wearing plastic lensed glasses that are very clear. Why not a plastic lensed flashlight that is equal, or almost equal to clarity of a glass lens, UCL, or borofloat.

Bill

 

[Lightraven]

The downside is that polycarbonate scratches quickly versus glass. If you take your flashlight into the field, it may get dirt and grit on the lens/window that gradually scratches it. My Surefire M6 window is still very clear despite going into the dirt for years now. But polycarbonate won't break.

 

[cdosrun]

The issue of the terminology has been addressed before, can't remember who or when. You are quite correct, the window is not a lens in most torches but I think the nomenclature is bordering on the same lines as most people calling a cell, a 'battery'.

While I am still waiting for my Novatac, I thought I would order a sapphire window and tritium bezel ring (just because I haven't had a light to modify like this).

I have ordered the SS Tritium bezel ring from 4-7s but I am a little unsure about the window; I have a feeling that this one is right http://theledguy.chainreactionweb.com/product_info.php?products_id=740 but could anyone offer any advice on it and whether any new o-rings would be necessary?

Thank you,

Andrew

 

[gunga]

Tis true, high quality sunglasses use optically clear polycarbonate, it is possible that a flashlight can do the same.

My main issue is the same as many others, I am a bit worried about scratching up the lense. Even basic lense cleaning get a lot more complicated when one is worried about scratching a plastic lense.

In any case, it's probably worth trying out the stock lense for a while. Keep in mind that many scratches can be polished out fairly well using common materials (eg, brasso).

I know this from extensive use and scratch removal of the current generation iPods. The forums are full of advice on keeping the fragile polycarbonate face scratch free.

 

[GarageBoy]

Let me ask, why Sapphire? Not that great of a light in light transmission and will shatter

 

[LukeA]

Let me ask, why Sapphire? Not that great of a light in light transmission and will shatter

Scratch resistance. Sapphire is very hard.

 

[TITAN1833]

The issue of the terminology has been addressed before, can't remember who or when. You are quite correct, the window is not a lens in most torches but I think the nomenclature is bordering on the same lines as most people calling a cell, a 'battery'.

While I am still waiting for my Novatac, I thought I would order a sapphire window and tritium bezel ring (just because I haven't had a light to modify like this).

I have ordered the SS Tritium bezel ring from 4-7s but I am a little unsure about the window; I have a feeling that this one is right http://theledguy.chainreactionweb.com/product_info.php?products_id=740 but could anyone offer any advice on it and whether any new o-rings would be necessary?

Thank you,

Andrew

I cant see any reason why you would need a new o-ring.yes the window will fit,