Aspherics?

[TorchBoy]

There is (or was) a guy a couple of blocks away who used to make his own mirrors, up to 36". He was so good at it he'd do the final tuning with a bit of rouge on his thumb.

 

[bluepilgrim]

Figuring with your thumb isn't too bad, but 36" is HUGE. You need a machine to do that: the thing is too heavy to grind by hand (unless you try to use a smaller tool on top, but then getting the shape you want is -- I don't know if anyone could do it except by machine. It would be hard to even lift a glass that size. Even 16" is really pushing it, working by hand.

But those mirrors are almost flat (F6 to F12, generally), and a flashlight reflector would need to be deep, with the focal point well inside of the curve.

A flashlight wouldn't need the same accuracy as an optical instrument, though, and being a little off can even be useful in creating some side spill and a softer spot. Maybe even a few different sections of conical shapes would be good enough, in practice. One of the things I find annoying about some of the lenses is that they project a square image if the led, along with the dark lines in the die, or with an image of the wires.

 

[dymonite69]

The deeper the reflector, the more light can be reflected - but it doesn't need to be wide at the opening. You could place a lens at the front to diverge the beam the required angle.

 

[TorchBoy]

Figuring with your thumb isn't too bad, but 36" is HUGE. You need a machine to do that: the thing is too heavy to grind by hand (unless you try to use a smaller tool on top, but then getting the shape you want is -- I don't know if anyone could do it except by machine. It would be hard to even lift a glass that size. Even 16" is really pushing it, working by hand.

But those mirrors are almost flat (F6 to F12, generally), and a flashlight reflector would need to be deep, with the focal point well inside of the curve.

I think he mentioned for the bigger ones just grinding out (angle grinder?) most of the glass to get the approximate shape. Most of them were F4, which I understand needs to be more precise than the longer focal lengths. Most people were :duh2: at his methods and and the results.

Sorry, this is all off topic.

 

[saabluster]

This idea that aspherics are not practical is a bunch of baloney. By the same reasoning that one comes to that conclusion then we can also figure out that all flashlights are impractical. Of no use whatsoever.

So let's see...I need to see across my 20 acre property and this Fenix LD05 cannot reach there so I should just throw it out.:thinking:

I can't EDC a Maxabeam so they never should have made it in the first place.

You mean that Surefire G2 doesn't take AAs!? Take it off the market!

Shall I go on?

You use the tool that gets the job done.

There is no reflectored light that can keep up with the throw provided by an aspheric light assuming the two lights are of the same size(gigantic HID lights excepted). What does this mean in the real world?

You will be able to see farther with the aspheric. In several situations this could mean the difference between life and death(Tactical or Search+Rescue). It could also just mean the difference between getting a good shot off while hunting.

The unique beam pattern of an aspheric has other benefits. The lack of spill is in many instances a very desired thing. The security officer or LEO on patrol needs to have a look at the property for perps and would rather not shine a bright light into the eyes of passing cars. Delivery guys or emergency personnel looking for house numbers benefit from an aspheric by not blasting a wall of light at houses as they go down the street waking everyone up.

A lot of guys like to survey their land while remaining in their truck. Generally they are using a spotlight in order to see far and therefore need a bright light. That spill that everyone loves so much will in this instance blind the user when it falls on the interior bits of the truck.
The same thing goes for boaters. The spill that hits the boat ruins their night vision. The spill from a reflector will cause the eye to constrict and now even more light will be needed to overcome this. That means more power has to be sent to the light. Then the battery gets larger and/or the runtimes decrease.

For a light intended to throw spill is an utter and complete waste of energy and makes it more difficult for the light to do its job. Need to see the path in front of you? You use a different light. Who in their right mind guides their way down a hiking trail with a spotlight?

People who truly understand flashlights will tell you that optics are the way to go. There is far greater flexibility in what can be accomplished when using optics. Aspherics can be designed to provide a flood type beam or ultimate throw and anything in between. Optics give you control of light and that is why they are the best option. I have understandably done a lot of work with optics. I have even designed my own proprietary optics that you will get to see in due time.

Saying that a particular light is not practical without some qualifiers attached like "for me" is almost always a sure indicator that you have little knowledge about flashlights or how the human eye works.

 

[gcbryan]

Saying that a particular light is not practical without some qualifiers attached like "for me" is almost always a sure indicator that you have little knowledge about flashlights or how the human eye works.

You've just done that haven't you...you've just written off anyone who prefers reflectors with no qualifiers attached.

 

[saabluster]

You've just done that haven't you...you've just written off anyone who prefers reflectors with no qualifiers attached.

As a matter of fact I have not. Try rereading it. When I speak about optics it is about the control of light. And no reflectors cannot match optics in that respect. There are other factors such as price and ease of assembly that come into play in the marketplace that make reflectors sensible.

 

[gcbryan]

How about a dive light used in limited viz waters at night. You may want throw to cut through the limited viz but you still need some spill to see where you are going.

How can an aspheric do that?

 

[saabluster]

How about a dive light used in limited viz waters at night. You may want throw to cut through the limited viz but you still need some spill to see where you are going.

How can an aspheric do that?

There are more ways to accomplish this than I care to go into. It can be very easily done using optical elements before the main lens or by changing the surfaces of the main lens itself to manipulate the light to where you want it. A very simple way is to use a diffused lens like the ones I was making for the DEFT at one point. It has an intense center that blends out to the edge in a very buttery smooth fashion. It did not get a lot of attention because everyone here was so enamored with the smooth len's beam. Anyway that is a very simple way to accomplish it but there are more complicated and directed ways to do it.

 

[gcbryan]

There are more ways to accomplish this than I care to go into. It can be very easily done using optical elements before the main lens or by changing the surfaces of the main lens itself to manipulate the light to where you want it. A very simple way is to use a diffused lens like the ones I was making for the DEFT at one point. It has an intense center that blends out to the edge in a very buttery smooth fashion. It did not get a lot of attention because everyone here was so enamored with the smooth len's beam. Anyway that is a very simple way to accomplish it but there are more complicated and directed ways to do it.

Well, I'm certainly not a hugh fan of spill to the degree that we generally see it today so I'm all for optics if a better result can be accomplished. I just don't see that for the most part happening so far. TIR at least reduces the spill intensity with the collimation lens which is good for me in general.

I don't particularly like the tiny XR-E spot and then a huge well defined circle of spill nor do I like the black and white cut off of aspherics as we generally see them today.

Something like the XP-G but with the spill gradually trailing off rather than a sharp outer edge would be good.

It sounds like that's what you are describing with the difussion lens approach while retaining the more focused center.

It seems that everyone is always asking for more throw in general purpose flashlights but then when using them in any way other than just for throw they are irritating due to the very bright center spot and too wide spill. If you cut all the spill off that doesn't work either except in dedicated throw uses?

I guess the cost of a better optic system is more than can be supported by general purpose flashlight usage.

 

[Popsiclestix]

Try an aspheric in a 10W Mag HID.

Lasts over an hour, hand carryable and throws a spotlight beam. It's completely out throws my Mag85 with SMO reflector, and lasts significantly longer to boot.

Surface brightness is the key to aspheric throw and HIDs are where you currently find the highest luminous flux density.

I'm waiting for someone to stick an aspheric in front of their higher powered 35/55/80W HIDs.

 

[Ian2381]

To make a P60 (SolarforceL2) a thrower,

Have anyone tried SKU 13907 from DX-30mm*14.3mm Acrylic Lens Optic.

Will this work?

 

[saabluster]

I guess the cost of a better optic system is more than can be supported by general purpose flashlight usage.

Reflectors=low hanging fruit for the flashlight companies. I think the reason reflectors have and continue to be dominant is that LED lights are relatively new. You cannot use the optic solution to very good effect on incans and that is where the market has been for generations. Second it takes considerably more resources to design and manufacture quality and innovative optics. Inova had the beautifully designed TIROS a while back. That is a very rare example of a company going to extra mile to make a better product. They ended up dropping it though. I'm sure some executive said "hey we could save $2 if we lose the fancy optic and replace it with a reflector." Looks good on the books you know. The general consumer won't know the difference anyway right? Sad. :shakehead