is it impossible to design a reflector that eliminates donuts

on mag adjustable focus ,has anyone ever attempted to design or make a real reflector that has no donut hole and is true spot to flood ?

qip said:

on mag adjustable focus ,has anyone ever attempted to design or make a real reflector that has no donut hole and is true spot to flood ?

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Would an LOP count?

is it adjustable and maintain same max brightness & intense hotspot

well mainly is it adjustable spot to flood with absolutely no donut hole ,cuz everything i read just says it smooths out the beam meaning eliminates rings& artifacts but i havent seen any mention of fixing donut hole

It depends on how far you take the focus, in and out.

If you truly want full spot to full flood, then no, at some point you get the donut, even with fairly high stipple or orange peel, but the smoother the reflector, the more throw, and the greater the artifacts and donut hole.

Bill

Too many factors.


IF you could place the bulb in the exact same place each time you focussed it, changed the bulb, or removed the bezel, and do this for each flashlight produced, yes, you could.

But, until then, you have to compromise in some way.

Max throw = artifacts
Smooth beam = less throw

Its the physics. You just can't change it. For the amount of money we are willing to spend, that is.

Could you have a reflector that can change its shape? It would change into one shape for throw and another for flood. Instead of changing the height of the light source, you change the properties of the reflector.

I know technology today could create a lense that can change its shape what about a reflector.:thinking: Could be expensive.

Gunner12 said:

Could you have a reflector that can change its shape?

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That could be interesting!

How about flexable aluminium? Not like foil, but stiffer, and using a spring-loaded mechanism to change its shape.

or like the iris of a SLR camera with many leafs that move independently in and out to change the shape of the reflector surface.

Yes, but too expensive. I had the same thing in mind that carbine15 said.

Another idea might be a bladder of material with a flexible mirrored substrate on it, and the pressure is changed accordingly.

EngrPaul said:

Yes, but too expensive. I had the same thing in mind that carbine15 said.

Another idea might be a bladder of material with a flexible mirrored substrate on it, and the pressure is changed accordingly.

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This doesnt strike me as durable at all. It would be wierd having a flashlight with 30 moving parts though.

Reading the thread from the top I said dynamic reflector as well.

Some modern astronomy telescopes have mirrors that are computer controlled to adjust for the seeing conditions. However those are minute adjustments controlled by computers on very large and precise mirrors. I don't think a flashlight reflector is build to a precision that will allow something that precise, especially at flashlight size.
Als add the fact that those mirrors only refocus the light to adjust for changes in the atmosphere, not convert the much biger range fo Flood > Throw.

Then my next idea is a liquid reflector. If the reflector can melt and re-freeze itslef that would be a possibility, though I am unaware of anything that works like this.
But... ferrofluids can be manipulated via magnetic fields to form all sorts of complex shapes. It might be possible to be precise enough to work, but the energy required to porduce and maintain the magnetic fields required is beyond what our current power supplies can do I think.

The final thought I have for the moment is optics. A system of lenses could probibly do what we want, but to the best of my knowledge it wouldn't be very practical in size or reliability of mechanical parts for an EDC or even a maglite.

Any other ideas? Just the top of my head here.

I read about a camera some time last year that used a liquid-filled bladder as a lens that could change shape to zoom/focus. Perhaps this could be adapted to some kind of TIR system? It would be expensive, but it would work pretty well, I think. I'll need to find that article...:thinking:

Or you could just use a diffuser when you need more flood. I use plastic shopping bags.