My take on the flood/throw debate.

[Spoonrobot]

There are a lot of things flashlight enthusiasts like to argue about, AA v. CR123A batteries, Surefire v. Everyone Else and Flood v. Throw.

For some reason the intensity of a flashlight's beam gets the ol' flashaholic photons in an uproar at times. Both sides will spew vicious comments and at times insult the other side over using a flashlight to see something right here or over there.

Personally I prefer throw because I live and work in a fairly rural environment and usually need to see things over there instead of right here. I do like to find a good compromise beam, a little flood and a little throw. The only problem is that one flashlight, even a variable focus model, cannot have both good flood and throw. It just doesn't really exist in a satisfactory manner.

My solution is the following. Take a light that is all flood, like the Zebralight H50 Q5. Take an aspheric lens and carry both. When you need flood use the Zebralight, when you need throw, hold the lens in front of the LED and see way over there. The bare emitter of the Zebralight gives a perfectly smooth flood beam and the aspheric lens give an amazing focus to the LED and throws extremely far.

Of course, the solution is inelegant and generally requires two hands to use but it is a cheap and easy way to make one flashlight act like two without any real lumen loss.







Anybody else playing around with aspherics? I've been using this same lens with my SolarForce T7 but haven't had much luck getting the focal lengths I really need to do a permanent install.

[edap617]

I will experiment using a lense with my flashlight this evening Spoon. Thanks.

[Spoonrobot]

It makes for some interesting beams. I got my aspheric lens from surplusshed.com but I've experimented with lenses from cheap binoculars and telescopes. The problem is finding the right focal length.

[prime77]

It makes for some interesting beams. I got my aspheric lens from surplusshed.com but I've experimented with lenses from cheap binoculars and telescopes. The problem is finding the right focal length.

That pretty cool though. I would have never thought that.

[Spoonrobot]

If you want to install one on an given light the way to find the right lens is to measure the distance from the LED to the stock lens in the bezel of the light. This is the focal length. Next you need to make sure the aspheric is the same diameter as the stock lens. It's hard to find the right lens for a permanent install but if you have the numbers you can do a quick search and find something that may work. Kind of a pain but it really pays off if you want a tight throw beam.

I'll do some shots of my Solarforce T7 tonight, the focal length is slightly off but it still gets pretty tight.

[bobofish]

Couldn't you also get a throwier beam and use a diffuser?

[NutSAK]

I really don't think flood/throw should be debated at all.  They both have their purposes.

I prefer to EDC a floodier light because I often need a light for close-up work, but if I'm outdoors I also want to have a thrower on me.  There are lights that have a very good mixture of both flood and throw.  A good example of that is the Novatac EDC series.

BTW, if you have a SAK with a magnifier on it, you could carry it for the same purpose.  I would be more apt to use bobofish's suggestion, though, and carry a thrower with a snap-on diffuser due to the difficulty of "focusing" the aspheric lens.

[Spoonrobot]

The advantage of aspheric v. diffuser is that most throw lights are generally larger and more cumbersome to carry than general use lights. So it's less weight and bulk for me to carry an aspheric with a floody light than a diffuser with a throw light.

Here's some pictures of the aspheric in action in front of a SolarForce T7. This aspheric lens has a focal length of 20mm, it's 3-4mm off so the beam is not as tight as it could be but it has significantly more throw than the stock reflector.

Stock:


Aspheric:

[NutSAK]

That's pretty impressive.  Can you use the light + lens easily with one hand?

[jzmtl]

I suppose you can get some kydex sheet and make sort of a snap on filter thing for the lense.

[bobofish]

Also, monocles really need to make a comeback!

[Spoonrobot]

That's pretty impressive.  Can you use the light + lens easily with one hand?

Yes, the bottom of the lens is convex so it will sort of seat itself and then I just hold it against the bezel with my thumb and index finger. I have a more appropriate lens on the way, this one was supposed to be for a D-Mini but the focal length was wrong so I've just had it bouncing around for a few months and decided to see which lights it would work on.