Focusing flashlights

Hello forum members,

Being fairly new to Candlepower forums I have a question about focusing flashlights. The old Mag lights with an incandescent bulb were flashlights that one could focus. I notice that Coast makes several focusing flashlights that have only 2 brightness settings. I also saw that Fenix came out with their FD41 which is a focusing flashlight.

I am wondering if there is something with led flashlights that makes it more difficult to design a focusing light, such as optics, characteristics of the led, or other factors. It seems that the high end lights are all fixed focus.

Just curious about how this works with the led lights.

Thanks.

Eric

Hey,
From what I can tell, they end up loosing alot of light to the sides that doesn't make it out the lense.. they don't have a reflector.. so they are not as efficient. Also they are bulkier.
Anyone correct me if I'm wrong

Most of the focus adjustable LED lights on the market are "zoomies" that is they have a lens in front of the LED that can be moved in and out. Far fewer but some use TIRs like the Coast lights and at this point only Fenix uses it's dual reflector setup. Zoomies have the best throw and while some light is lost making them less efficient there is a debate on how important that is. TIRs are very efficient but don't have the same throw, they do produce a much nicer beam profile more like a conventional reflector light. The Fenix system, well I guess I personally think it's kinda meh, at the very least the light's specs aren't very impressive.

For some reason a lot of people are really down on zoomies and part of me thinks it's just a historical bias since most of them have been cheap lights with junk internals. Performance wise well made zoomies are very practical. At close range they produce a very even flood and spread their light out such that a lower mode will illuminate nicely. Once zoomed in they will out perform any given reflector light for size given the same LED. (but this is often not shown since most of them on the market use crappy LEDs seriously underdriven) And at the same time put a lot more of their available lumens into that long range beam, the tradeoff is a normally square beam and the total absence of spill meaning you generally want to switch them back into flood mode to use them close up. In the end it is a personal preference I guess but I suppose I'm a bit biased since I have a special love for aspherics and zoomies which is why I build them.

If I may guess, I think it is similar to the differences of opinion about clickies or twisties. The clicky crowd likes the quick utility, and the twisty crowd insists on durability. Compared to focusing flashlights, fixed focus flashlights have less moving parts, so less wear to endure in use and less possibility of failure, just like twisties have fewer moving parts compared to clickies.

Focusing flashlights started with incans and most of them just moved the reflector up and down with the bulb stationary and most often were accompanied by horrible ringy beam patterns that made things sometimes even more difficult to see. We then had LED lights that mimicked the old incan lights by a reflector and a stationary LED module these worked better than the old incans but still were not the same beam pattern as todays focusing lights. We also had LED lights with optics to focus beams that were not adjustable. Often these lights threw out a ball of light that, although was useful because you couldn't zoom out you had no way to see much other than in that circle of light. Todays focusing lights mostly move optics in/out with a stationary LED and these IMO work better in light beam quality but as others have said the loss of lumens can be very noticeable in the optics you can really notice it while ceiling bouncing the light.
Personally I like zoom lights but I also like reflectored lights too. I think zoom lights are more fragile and often you grab them to use and have to adjust them too much (because you can).

Some of us liked that circle of light.

Lynx_Arc said:

Focusing flashlights started with incans and most of them just moved the reflector up and down with the bulb stationary and most often were accompanied by horrible ringy beam patterns that made things sometimes even more difficult to see.

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The rings have nothing to do with incan or focusing, but is entirely the design of the reflector. Whomever designed Solitaire intended that outer ring collimating extra light there at the edge of the spill. If you could replace a Soli reflector with an orange peel reflector, when properly focused, there would be no outer ring, but the light that was there would instead be evenly spread into the spill.

greenlight said:

Some of us liked that circle of light.

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+0.99

When it comes to zooming ability with incans I think it was much introduced due to the extreme intensity difference between the hotspot and spill. A traditional incan often is a very long distance OR very short distance tool: spill works at very short distance and hotspot at very long. Between the long and short distance the hotspot is still too small(and with a strange shape instead of a uniform circle) to cover a useful area and the spill is too dim to even be noticed. With the introduction of LED flashlights we got a wider hotspot and a much brighter spill. Well, Surefire incans are better constructed than typical warehouse incans but still the spill is much dimmer than LED at the same output.
I guess Zoom LEDs have not been very popular because the zooming feature is more sensitive and that it's not really as important to have because of the good allround beam character of a standard reflector LED light.

scianiac said:

For some reason a lot of people are really down on zoomies and part of me thinks it's just a historical bias since most of them have been cheap lights with junk internals.

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This pretty much hits the nail right on the head. Even the best zoomies out there are fairly low quality lights with crappy emitters and fairly low output. High CRI or even just plain neutral tint? Forget it! You're probably going to get a 3-4 year old cool white XM-L2 at best if you're lucky. In the end, the sole purpose of the zoomie is to try to make up as best as you can for the crappy output of a cheap light. The idea is that, if output is pathetic, the light can still throw well if all that low output is concentrated in a pencil beam. But you have to be able to zoom in for a floodier beam for closeup lighting needs. When all is said and done, a better quality light with better output just does a better job illuminating both near and far than a crappy zoomie. Could a quality zoomie do better? Perhaps. But then you have to deal with the other shortcomings of soomies, like waterproofing.

StorminMatt said:

This pretty much hits the nail right on the head. Even the best zoomies out there are fairly low quality lights with crappy emitters and fairly low output. High CRI or even just plain neutral tint? Forget it! You're probably going to get a 3-4 year old cool white XM-L2 at best if you're lucky. In the end, the sole purpose of the zoomie is to try to make up as best as you can for the crappy output of a cheap light. The idea is that, if output is pathetic, the light can still throw well if all that low output is concentrated in a pencil beam. But you have to be able to zoom in for a floodier beam for closeup lighting needs. When all is said and done, a better quality light with better output just does a better job illuminating both near and far than a crappy zoomie. Could a quality zoomie do better? Perhaps. But then you have to deal with the other shortcomings of soomies, like waterproofing.

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Wow! You've had much worse experience with focusing lights than I have. I'm quite fond of my Coast HX5. I deploy it quite a bit more often for daily tasks than my Zebralight SC52W because of the variable focus, momentary and simple UI.

I am the happy owner of the FD41, and I also had the FD30, and I personally think these flashlights blow most of these theories out of the water. I do agree with some of the points made, though... I posted some pictures of both the FD30 and FD41 (link of FD41 pics below) on other threads, and although the quality of the pictures was not professional standard, you will be able to see the difference between spot and flood. And trust me, these lights are 100% waterproof! I tested them myself. From the pictures you cannot clearly see the flood, but the spread is great. I certainly have no gripes whatsoever about any of these lights.

http://www.candlepowerforums.com/vb...D41-focusing-ring-overview-and-first-thoughts

Thanks to all who posted about focusing flashlights. I need to ask what a TIR is and how is it different from a reflector type focusing flashlight. I also wanted to know which lights are the better made focusing flashlights today? I had an opportunity to use a coast light. It was the one in a silver housing kind of heavy but it seemed to be good about 720 or so lumens on high. I used it while helping a friend do some work and the low level and adjustable focus was quite useful. I did not get to try it outside. Which focusing lights do you think are the better ones? Which LEDs are now the highest output? There seems to be a lot to the design of these lights.

Eric

I always thought the lack of focusing flashlights was down to certain companies who did it originally having patents which other companies wanting to do this had to find a way around which took some time.

Having used Maglites for many years, I have to say I've never wished for a focusing light since saying goodbye to Maglites. I've found the pre-focused reflector or TIR lights from other brands are much more to my taste.

FYI a TIR is generally a pre-focused optic which projects the beam a certain way, often used for more throw or more flood beams. The TIRs can be configured to do different things. TIR stands for Total Internal Reflection.

How about a little history?
Believe it or not the quest for the perfect beam did not begin in 2000 when CPF was invented.
From day 1 of flashlight history there was a quest for more brightness along with a better quality beam.
Some sought to provide a flashlight that could throw or be used to light an area.
Nothing new under the sun here. But the question "why high end companies shy away from zoomies" pretty much boils down to the demand.
The demand for a better overall beam far exceeds the demand for adjustable beams.


On the left is an adjustable


The bulb stayed put in a collar.
It took a lot of twists to change things and as you know folks are in a hurry. So that idea didn't really catch on.


A slider zoomie.
This one provided side by side on/off spot/flood


An elegant slider zoomie


The bulb moved in the elegant zoomie.
The reflector stayed put. It resulted in a good combo of spot or spill but when slid to zoom caused the beam to appear chaotic. Bulbs mattered a great deal in that one.


Early optics based dual function beam


An attempt to have spot/spill and a good beam.

These ideas were hit and miss throughout the ages until the Maglite cam system was released.


The reflector rotates around the bulb
Between much brighter reflective material and better bulbs these things changed the world of zoomies.


Brinkmann zoomie.
These guys along with Streamlight and others tried the twisty zoom like the vintage one above. Again the beam suffered although that Brinkmann showed had pretty dang good looking spot.


Brinkmann had some good ideas.
Unfortunately Brinkmann decided to battle Maglite in Wal Marts and lost.


Modern sliders
These days the zoomies are made to slide and are a lot better thanks to the magnifier type lens. They are a big hit with plumbers, a/c repair folks and various blue collar oriented duties. Those folks don't care about beam quality as much as they just want an adjustable light while packed inside a crawl space. And the smaller size provides them as much light as those big Mags but fits in their trouser pockets.

The fashion industry is what drives flashlights these days. Seriously. Even some of the big names are making lights based on the wants of the flashaholic. Zoomies are not on those "wants" list because they just don't have the quality beam of fixed lights.
Maybe some day. Their are a couple of companies still trying to do better. Apparently Fenix is one.

There is a fundamental difference in how light is produced from a typical LED compared to an incan that does affect how easy they are to make into zoomable flashlights ("zoomies").

Incandescent - Due to the nature of how reflectors work, it's easier to make a focusing reflector when the light is emitted backwards and to the sides into the reflector.
(a) The focal point of a reflector is usually raised above the base of the reflector. In an incandescent, the light source is a point located at the tip of the light bulb. Light is emitted in a sphere from this point source. This light can then reflect downwards and sideways into the reflector (forming the spot). Unreflected light forms the spill. Adjusting the zoom by screwing or unscrewing the bezel simply moves the light source on and off the focal point.
(b) Incandescent bulbs emit most of their heat as infrared light which is radiated out of the front of the light together with visible light. Very little heat conducts backwards through the housing so elaborate heatsinking isn't needed.

LED - in an LED light, the light isn't emitted as a sphere. Instead it is emitted in a cone shape from the top of the LED. Nothing is emitted backwards. This creates a couple issues:
(a) Since the LED doesn't emit light backwards the light source it usually isn't at the best focal point of the reflector. Instead it is almost always located at the base of the reflector instead of above it.
(b) high-powered LEDs generate a lot of heat. This heat conducts backwards through the LED mount and then to the sides of the metal light body. Because of the need to absorb this heat, the LED is usually mounted on a flat metal board called a "star", further limiting focusing options. A retracting bezel like in an incan maglight may be less practical as the star may get in the way.

Perhaps because of the difference in how light is radiated between LEDs and Incandescents, zoomable LEDs typically do not use the same zooming mechanism as the old mag lights. That said, there ARE many zooming LEDs, but they usually use a different method too zoom.

Types of zoomable LED Lights:

(a) Aspheric Lens (magnifying glass) - this is the simplest and most common type of LED zoomie. This type of light has an aspheric lens (like a magnifying glass) mounted on the front of the light and no reflector. Most zoomies of this type work by having the lens mounted on a moveable bezel. With the lens extended, the LED falls at the focal point of the lens. This produces maximum throw, and a projection of the LED's surface. There are many different zoomies that work with aspheric lenses like this. Some have a fixed lens and a rotating mechanism that raises or lowers the LED. Others require a simple push-pull of the bezel. Still others require the bezel to be unscrewed. Almost all budget zoom flashlights use aspheric lenses. A few premium lights, like Lenslight, also use them.

The flood beam of this type of zoomie is generated when the lens is retracted. This defocuses the hotspot. Also, because the bezel is no longer in the way, much more of the LED's cone of light passes directly through the lens yielding more lumens. Light output is typically a perfectly uniform circle with sharp edges and no hotspots. However, some less well designed aspheric zoomies might feature floodbeams that contain ugly rings around the circle. These are caused by reflections inside the bezel or lens mount.

Most aspheric lenses are made of optical acrylic, but some more premium ones have glass or even coated glass lenses.

Advantages: Simple construction. Good throw, Cheap. No major patent issues.
Disadvantages: Many are poorly made. Flood beam may be too narrow to be useful (caused by design defect not allowing bezel to retract far enough). 50% or more of total lumens are lost in spot mode due to sides of the light cone from the LED hitting the inside of the bezel rather than the lens.

(b) LED Lenser zoomable TIR optic (lighthouse optic) - this more sophisticated zooming mechanism consists of a single piece TIR (Total Internal Reflection) optic with 2 elements. the center element is a simple aspheric lens. the side element is a TIR reflector which catches light from the sides of the LED and reflects it forwards. This type of optic contains a large cavity in the center. The LED is mounted on a post which fits inside this cavity. In spot mode, the LED is at the centerpoint of both elements of this optic producing a fairly tight beam. Because the optic surrounds the LED in both flood and spot modes this optic has a number of advantages compared to a basic aspheric lens.

The custom TIR optic found in LED Lenser style lights are always made from optical acrylic plastic.

Advantages: no loss of lumens in both flood and spot mode. Spot beam may be more attractive than with an aspheric. Often less travel distance of the bezel compared to basic aspherics due to shorter focal lengths.
Disadvantages: LED Lenser patent. More complicated optic and head construction due to need to mount LED on a post. Potential heat issues.

(c) Variant LED Lenser style TIR - Same as LED Lenser optic with the exception that both elements of the TIR have different focal points. In "spot" mode you get much less throw than either of the above options, but the spot beam looks more like a traditional reflector flashlight with a combination of both spot and spill. Example: recent model COAST lights.

(d) Moveable reflector: Some cheap Costco LED lights advertised themselves as "zoomable" because they had a bezel that could screw or unscrew a few mm, allowing for the LED to be moved slightly off the focal point. While decent budget lights I don't really consider these proper zoomies because the only settings were basically "spot" and "slighty less focused spot". the bezel travel simply wasn't enough to make it viable as a close range flood light.

(e) Fenix FD30 style 2-part reflector: This is a method of zoom unique to this one fairly new model of light. The Fenix FD30 is a conventional reflector light, but with the reflector broken up into two pieces. the bezel containing the outer reflector and lens can retract placing it behind the inner reflector and out of the path of the beam. In flood mode the FD30 produces an extremely wide flood with a very wide and diffuse hotspot (from the tiny inner reflector). In spot mode you get a wide even narrower flood surrounding a small hotspot. I'm not sure how well the FD30 will do though as it's mechanics are extremely complex and throw is mediocre.

* * *
A note on waterproofing in zoomable LED lights. One other issue common to most zoomies: waterproofing. most zoom flashlights involve a moveable bezel. Changing the position of this bezel to cycle the zoom also changes the internal volume of the light. If the light were air-tight, zooming is awkward because air pressure equalizing will cause the bezel to retract or extend into whatever position it was in when the battery compartment was sealed. Because of this, most zoom flashlights, including virtually all of the convenient push-pull ones, are intentional not waterproof. Usually an o-ring is omitted so air pressure can equalize and the bezel will stay in whatever position you move it to.

Waterproof zoomies typically need much stiffer zoom mechanism to prevent air pressure from moving the bezel. They can accomplish this with extra o-rings or screw-on threaded bezels. The downside is an extremely stiff zoom mechanism may not be nearly as convenient for one-handed operation.

* * *

Having experimented with lights using all of the above zoom mechanisms, in my opinion the LED Lenser method is the best. It's the most efficient design for lumen output in all modes and produces a pleasing beam pattern in both flood and spot modes.

I found a real good use for zoomies.
I use it for spotting bouys in the channel at night when boating. Having a real long distance thrower
with little spill is very useful. I use a zoomie custom from cpf italia called the cometa.
I was going to try a laser but the reflections could harm your eyes if not using special glasses!Lots of reflections from whit deck and SS bowrails was to much of a risk so I found zoomies.

Fireclaw18 said:

There is a fundamental difference in how light is produced from a typical LED compared to an incan that does affect how easy they are to make into zoomable flashlights ("zoomies").

....

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Clipped for brevity.

Good post FireClaw

Thank you very much Fireclaw for your very thorough explanation of focusing or zoomie flashlights. I really appreciate it.

Eric

bykfixer and Fireclaw18 have elevated this thread to the level of sticky, or at the very least, should now be included in some list of "threads of interest." Here's a fascinating, thorough yet concise history of the technology of focusing flashlights. Thank you both for sharing!

scianiac said:

Most of the focus adjustable LED lights on the market are "zoomies" that is they have a lens in front of the LED that can be moved in and out. Far fewer but some use TIRs like the Coast lights and at this point only Fenix uses it's dual reflector setup. Zoomies have the best throw and while some light is lost making them less efficient there is a debate on how important that is. TIRs are very efficient but don't have the same throw, they do produce a much nicer beam profile more like a conventional reflector light. The Fenix system, well I guess I personally think it's kinda meh, at the very least the light's specs aren't very impressive.

For some reason a lot of people are really down on zoomies and part of me thinks it's just a historical bias since most of them have been cheap lights with junk internals. Performance wise well made zoomies are very practical. At close range they produce a very even flood and spread their light out such that a lower mode will illuminate nicely. Once zoomed in they will out perform any given reflector light for size given the same LED. (but this is often not shown since most of them on the market use crappy LEDs seriously underdriven) And at the same time put a lot more of their available lumens into that long range beam, the tradeoff is a normally square beam and the total absence of spill meaning you generally want to switch them back into flood mode to use them close up. In the end it is a personal preference I guess but I suppose I'm a bit biased since I have a special love for aspherics and zoomies which is why I build them.

Click to expand...

Good posting here. I feel the same about zoomies, scianiac. I've bought five over the past 3-4 months hoping to find a quality light, but like you said... underdriven, crappy LEDs is all I find. The Jaxman Z1 XHP50 is the exception... it's the best I've been able to acquire so far, but even it leaves something to be desired in terms of size and build quality.

If you would like to direct me towards a better choice or if you'd consider selling one you've made please don't hesitate to contact me via PM or email ([email protected]). Thanks!