Hard to solve light problems!

There is one problem in the light world (flashlights and headlamps) that drives me crazy :)

When I'm outside I want a beam to be 180 degrees (for the spill anyway) and if I need throw then I want the hotspot in the 6-10 degree range (XR-E/XP-G).

If I don't need throw then there's no problem. Put a piece of tape or diffusion material over the lens and you have 180 degrees of light so there is no sharp cut-off to the light in your vision since it's either totally diffused or the cut-off at 180 degrees is beyond your peripheral vision.

Lighting is more natural this way and there is light around your feet as well as where you are looking.

The problem is when I do want throw in a light and don't want that sharp cut-off in my vision. Most lights with throw tend to be about 90 degrees for spill and 6-10 degrees for the hotspot. If you diffuse them to do away with the cut-off you lose the hotspot and therefore the throw.

The best solutions I've seen are some TIR optics that greatly reduce that sharp cut-off mainly by just reducing the intensity of the spill. It is also possible to use a very light diffusion effect film over the lens which will reduce the sharp cut-off effect and will reduce but not eliminate throw so it's a decent compromise.

Does this effect bother anyone else and if so what have you do about it (if anything)?

I am describing two light as far as pure flood or total diffusion lights as the ones that I don't have a problem with and then there are the throwers that I do have a problem with.

There is no problem indoors. For one thing I don't generally use flashlights indoors but whether it's indoors or close in outdoors I would just use flood or diffused lights.

When I need some throw (not a dedicated thrower) but don't want the sharp cut-off (spill to darkness at the outer edge) that's where the problem is. This occurs with hiking and headlamps frequently. I need to see ahead a bit and I need to see where I'm walking.

Sort of like saying that I want a car that has the carrying capacity of an SUV, but handles like a sports car...

Be nice to have both in the same package, but probably ain't gonna happen.

But a different way to look at is is just put yourself 2 years back in history when the only choices you had were luxeon LED's or maybe an Xp-E or XR-E. The XR-E's had awesome throw for it's day, but VERY little spill. New XM-L throwers have more spill today than pure floody lights had 3 years ago. So lights are evolving, now maybe someone will come out with a "stepped" reflector that will give a focused hotspot and also a wide spill.

I think reflectors are the next item that will evolve in the flashlight world, at least until battery capacities increase.

Is probably as near as you'll find in the budget world..though it's far from perfect.

(Review) https://budgetlightforum.com/t/-/2720

OK, I'm doing a little experimenting tonight (just starting to get dark). I have a Zebralight H51f (frosted) and a H51 (clear). I took a piece of translucent tape and using a hole punch made a hole in the center of a piece of this tape and put that over the clear lens of the H51.

My intention was/is to diffuse the outer edge of the spill (which will also reduce the hotspot given the way reflectors work) to keep some throw. The hole in the center if small enough would only let the spill out (thereby doing nothing) but the hole isn't that small so some throw is retained.

I've tested in out in a semi-dark garage and basement and it has a more directed beam (throw) than the H51f. I'm going to make the hole bigger and see if the throw improves again while still retaining the diffused edge.

Before I enlarge the hole any more I'm going to wait until it is a bit darker out side to have a real world comparision with the smaller hole and the soon to be larger hole.

More results later!

The bottom line is that I'm leaving one piece of tape over the lens of the H51 with the original sized hole in it. The edge is now diffused and it does throw much better than the H51f.

I tried enlarging the hole but since the area is so small in the first place enlarging the hole just resulting in the diffused edge effect going away so I went back to the original sized hole.

So now it has a diffused edge, doesn't throw as far as it originally did (expected of course) but does throw further than the H51f. Now both beams are pleasing and there is a distinction between the two lights (which I wanted to maintain of course)

Both are now good hiking headlamps and serve as spare battery carriers for the other with one being a little floodier and one having a little more throw.

I can't say for sure if the throw can be attributed to the hole in the tape since I already know that tape as a diffuser maintains a little more throw than frosted glass. The only way I would know for sure if the effect is appreciable would be to now fill in the hole with a piece of tape to see if throw was diminished.

Given how hard it was to punch a hole in tape in the first place I won't be doing that final experiment :) The beam is as I wanted it and that's good enough.

The heat with a LED is out the back so the lens isn't an issue. Try it. Turn your light on and touch the lens...it isn't hot.

What you are talking about I've tried just to see the effect and I couldn't really see one. It wouldn't brighten the spill since it already is the spill. It should diffuse it a bit but if anything would make it a bit less bright (just like most diffusers do).

It would most likely also lessen the hotspot since by the time you get to the lens the reflector has already done its collimating all over the reflector and you would be diffusing some collimated rays that could be contributing to the hotspot.

Once you get to the lens putting anything over it can't help but reduce the hotspot to one degree or another (as far I know). It's more effective near the edges but it collimates all the rays all over the reflector.

What I did either did nothing that solid tape over the lens wouldn't have done (maybe Dr. Jones can say for sure) or it preserved a bit more throw while the rest of the tape diffused the majority of the light including the cut-off at the edge which was my major objective. Tape (even without the hole) allows more throw than a frosted lens.

I followed up with the experiment tonight and it definitely works. This time I used a piece of diffusion material that I don't usually experiment with. I have a limited supply and therefore use it to completely diffuse my favorite lights if I'm not concerned about throw at all.

There was a small scrap piece of diffusion material off to one side so I punched a hole in it. I also used a smaller diameter light tonight. I have a cheap DX angle light using 1 CR123 and XR-E R2 and it's driven hard. So it's bright, throws very well, and has a head of smaller diameter than my Zebralight H51 that I was using last night (with tape).

It was easier to make the hole (using a standard hole punch) in this thicker diffusion material than it was last night using tape. Since the head diameter was smaller that made the hole punch hole proportionally larger (therefore increasing the effect).

I was also able to shine the light through the solid diffusion material to see that effect and then slide the light over to the small scape piece with the hole. The piece with the hole definitely throws further than the same piece of material without the hole. The hole was large enough that you could tell if I made it any larger the diffused edge effect (that I also wanted) would start to go away.

So a hole in the center of diffusion material will allow more throw than with no hole and you do need a certain percentage of diffusion material to remain around the perimeter to keep the diffusing effect instead of the harsh cut-off.