Aspheric snap-on to enhance throw

After playing with the KD aspheric and LED assembly kit for maglite I've become fascinated by the capabilities of aspheric lenses to throw far.
I've had great fun with the kit - but there is simply no way that 3D mag is going into my pack when I'm camping, hiking or doing other outdoor stuff - it's way to big and heavy. Unless there is a dedicated need and task for a long range searchlight-like capabilitie I'm not ever going to lug that big thing around. (And if I DO have a qualified need for a REAL search light I'm going to get a proper tool for that job. . . .)


What I do carry is the equivalent of a 2AA light (fenix ld2). Plenty of light for most I could ever use a light for except it doesn't really throw really far. I'm wondering how far that light (or a similar one) could throw with an asperhic lense. Of course, with the reflector in place there would be some ugly glare - but that does not really affect the projection of the sentral beam, does it?


I'd like to know the community's response to this idea: What about making a "snap-on" asperic lens kit for your EDC or "go hiking" light? In its simplest form it would be simply to put a lense into a rubber sleeve (such as an "anti-roll" thingy) that fits over the head and can be slided back and forth to focus. Of course there is no upper limit to how sophisticated this thing can be.

People do bring around diffuser caps - this would be the oposite, a "far throw cap" to give a general purpose light at least a decent amount of throw.

I'm avare that using aspheric with a reflector light will give you ugly glare and lots of weird artifacts. But that will not affect the central beam (Unless you're blinded by the glare). The central beam may be/will probably be less intense than in a dedicated asperic light.

I do apologise for the notion of bringing one light LESS into the woods and replace it with a less-than-optimum performing snap-on thingy .
I guess I'm not a proper flashaholic yet :candle:


So what do you think - would the performance of a "snap-on aspheric" on a general purpose flashlight (such as fenix LD2/LD20) give enough throw improvement to be worth the hassle?


The boring alternative is of course to buy a led lenser or a similar light with good focusing alternatives. But that is not what I'm asking . .. . .

My initial reaction is that, in some cases, it might be hard to get the snap-on close enough to the emitter to attain optimal focus based on the existing architecture of a given flashlight.

That being said, I'd love to have something like that to play with!:candle:

Interesting idea. However, most aspheric lens lights that work well do so because they have very very short focal lengths. They're usually placed not far away from the emitter -- closer to the emitter than the ordinary window glass on a stock maglite, in fact.

If you were to "snap-on" a loner focal length aspheric lens, such that it was in focus with the LED, I don't think there would be much of an advantage anymore, as the "snap-on' aspheric would be gathering a much smaller "cone" of light, even aside from any glare issues. Not only that, you'd have extra losses from the stock window reflections (with a diffuser this doesn't really matter, as you are trying to diffuse/scatter the light), which will cut throw even further.

Also, emitters that are good for reflector use, are typically bad for aspheric use, and vice versa. A SSC emitter, which will work well in a reflector light as it emits greater light toward the sides, will work poorly behind an aspheric for the same reason. I can't think of very many cases where the "snap on" reflector would give you much improved throw compared to the stock (unless the stock is almost 100% spill to begin with).

Fact is, diffusion is really easy to do after the fact. But tacking on a collimator and getting decent results after the fact is really really hard. You'd be best off designing a purpose-built aspheric light (or even modifying a light like your small EDC to work well with an aspheric lens) -- THEN carry along a diffuser for when you don't want the throw.

OR carry two lenses, one clear, one with diffusion film applied to it. This configuration will actually give you similar beam profile to reflector based lights, but without as much glare (since the "Spill" beam won't be a direct line of sight to a bare emitter... which is pretty awful if you're on the receiving end).

Would be easier to use a fresnel lens.

I carry a Bausch and Lomb magnifying glass that has 3 different lenses, and have had some interesting beams holding that in front of an L2D. It's not easy bringing the light into focus, but it concentrates the beam when lined up right.

Check out this post by Crenshaw, I think it's right up your alley.
https://www.candlepowerforums.com/threads/202346

Yes, that is EXACTLY the thing I had in mind. Thank you - that thread somehow eluded my search yesterday.