Why use a domed lens?

Some modded lights use a domed glass lens instead of a flat lens. Is there an advantage to this?

I can only guess:
- might add to beam collimation for a tighter beam with more throw
- could be tougher upon frontal impact
- looks cooler
bernie

EDIT: which modded lights are you talking about? I am only aware of SF production lights with a domed lens ...

Longbow said:

Some modded lights use a domed glass lens instead of a flat lens. Is there an advantage to this?

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some make a spot like the Inova X1. i dont like those beams!

Kiessling, thanks, I assumed some modders were usinging domed lens because the Shoppe as offered them to their customers for a long while.

nemul, I know of the focussed lens of which you reffer, but I was talking about the non-focussed varriant such as the 29.3mm item that is listed at the Sandwich Shoppe. Thanks.

Oh ... so maybe there are modded lights with domed lenses then ... ???

Kiessling, I know that my intellect doesn't match yours, but derision doesn't become you.

Longbow said:

Kiessling, I know that my intellect doesn't match yours, but derision doesn't become you.

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Longbow, I'm pretty sure there is no derision involved here, just a genuine interest as to which custom or modded lights were using them...

I have reworked a late L1 and KL1 to McR20 and gone to flat windows. The SF domed window is actually a lens. I'm not up to speed on optical stuff, but holding one at arm's length makes things look farther away.The inside of the SF lens has a much greater radius than the front of the optic behind it. :shrug:

Larry

Oh :green: ... I am sorry if I did sound like mocking you ... which I didn't ... but as B@rt said ... I am just curious if there are such domed custom lights, especially since the shoppe sells the lenses.
Given the scope of available custom lights these days ... who can know them all?
bk

I'm not sure that this is what you're talking about.



The head is by "d'mo" (LUX I) and the "N" sized body is by "jets22". Both were created as a mod to an ARC AAA...I put them together to make a new flashlight. I don't remember if the lens is full ball or a half ball. I think the balls are still for sale at the Sanwich Shoppe. The flashlight has a VERY tight SQUARE beam with practically NO side spill.

The domed mineral glass lenses from the Shoppe are just for the "cool factor". They don't affect the beam in anyway. They are not like the domed magnification optical lenses which are usually pretty thick.

I have em on some of my McLux PR heads and honestly I forget they're even there. Not very noticeable IMO unless you are really looking for it.

I assume the dome shape would add more strength to the lens but to me it feels like there's more chance of something striking the lens easier if dropped or whatever caus it protrudese out further which is not much at all. I have em on the McLuxs that never leave the house anyway. No big deal, I don't think the mineral glass is that easy to break, domed or not, unless really abused.

Thanks all for the input. I've decided to pass on the domed glass, and because I'm not impressed with the UCLs' on my other lights, going to order flat mineral glass lens.

Sorry Kiessling for my interpretation of your post.

What is it about the UCLs you have that you dislike? Too thick?

I recently bought a Vital Gear body as a host for a TW0K-modified BOG module and it came with a domed lens. At first I wasn't sure what I thought about it, mostly thinking that it would widen the hotspot and reduce throw but comparing it to another light with a flat piece of AR-coated glass, there is no, or very little, difference. I think the lenses need to be convex on both sides (as in most telescopes) or need to have two different degrees of convex-ness (? - such as with eyeglasses) to magnify or shape the beam.

I was told that the convex lens pretty much gets rid of the need for AR coating, making it non reflective, or at least radically less reflective than a flat lens.

I am pretty sure Domed lens on lights lie the Surefire U2,
are so the lens does not Reflect light as much.
So the enemy cant shine a light on you, and it light up the lens,
giving away your position.

~John

cratz2 said:

I was told that the convex lens pretty much gets rid of the need for AR coating, making it non reflective, or at least radically less reflective than a flat lens.

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so you would put the "domed" part facing the reflector? hmmmm

jtice said:

I am pretty sure Domed lens on lights lie the Surefire U2,
are so the lens does not Reflect light as much.
So the enemy cant shine a light on you, and it light up the lens,
giving away your position.

~John

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That makes total sense.......nice thinking tice, can anyone verify.

I'm impressed with all of the knowledge flowing my way. I'll bet your right about the anti-reflrctive property of a domed lens....gona give it a try.

Darkzero, try as I may, I can't notice an output/throw increase with the UCL. Maybe it's my old eyes.

If the difference in brightness is less than 20% ('twas 20%, right??) human eyes won't pick it up. That's because we can measure linear increases in brightness, but our eyes perceive light differences on a logarithmic scale. Or so I keep hearing 'round here...

If the difference in brightness is less than 20% ('twas 20%, right??) human eyes won't pick it up


And when you account for your eyes adjusting for the a lower intensity light, you notice it even less

(assuming not too much near spill to kill the adaptive response)