Zoom lights vs Reflector lights

Hi. I have written some general information just because I have a lot of other things I should be doing and my addiction to lights is how I procrastinate. I am not so sure that my technical understand is 100% correct and therefore would like to ask that you comment on this. (in a nice way please)

Before we start please take note that I am in South Africa and shipping to US is crazy so don’t think I am here to sell. My on-line sore also does not accept international payments nor Paypal so don’t bother to ask.

Zoom lights vs Reflector lights
When buying a light, you might be curious as to what the benefits are for a zoom light vs a reflector light.

Firstly you need to understand how reflector based lights work: below is a illustration with two pictures showing the Extreme 1000 head lamp in action.

An LED has a beam angle of 120-180 Degrees. The hot spot that can be observed with most reflector type lights are the result of the outside of the LED beam pattern that is folded and directed by the reflector. There are some losses due to the imperfect reflection surface of the reflector, but it is minimal. In this example the red part is folded and redirect forward, where the middle section leaves the light unaffected. The shape of the reflector is very important. The majority are parabolic with the focused point on the LED. There are two ways to increase the hot spot of a reflector type light. The first is to make the reflector deeper, and the second is to make the reflector wider. In both cases more of the light emitted by the led is folded and directed forward.

The alternative to a reflect type light is the fixed accumulator lens which works on the same principle but also focuses the light with the optics.

The advantages of reflector type lights are that they make use of more of the available light as well as having a combination beam with both flood and focused areas. Interestingly this is also their disadvantage: The reflector type lights allows you to see both far and near but do not provide a uniform beam. This is ideal for cycling and search and rescue but not for trail running, map reading or working with your hands.

Zoom lens lights.

Depending on the design, the lens or the LED position can be adjusted to change the distance between the two. As the distance changes a different part of the beam emitted by the led is captured and deflected. Below shows two illustrations which depicts the light in focused mode or flood mode.

Focused/Zoomed mode:

When the distance is the greatest the lens catches only the light that is travelling directly at the lens. When the light enters the lens its angle is changed and then travels in a focused beam. As can be seen, most of the light is wasted when the light is in this mode, although the beam is more concentrated to some extent. The little amount of light are more directional and concentrated and therefore do not disperse as much, allowing you to see further. This is helped by the fact that there is little to none other light to over influence the eye.

The below illustration shows how the lens only captured the top part of the light emitted by the led. If it is assumed that the amount of light is uniform over the LED beam angle, which to some extend it is, then a significant amount of light is on the outside of the beam. just to illustrate we made a quick calculation based on area and in this example 86% of the light emitted would be wasted. This should in reality not be as dramatic because the spatial distribution is not uniform. It does show that a significant amount of light is wasted in zoomed mode.

Flood mode:

When the light is in the flood mode the distance between the lens and the LED is the smallest. Most of the light is captured which is composed of light at different angles. This results in an even beam.

Even with the lens being very close in most Zoom type lights there are still a significant amount of light that is not captured. The Extreme 1K is an exception. Its LED is moved up flush to the lens when in flood mode but some light still hits the outside adjusting ring.

The benefit of a zoom type light in flood mode is that the beam pattern is smooth and uniform. This is ideal for illuminating working areas, for example map reading or fixing something. Trail running is also benefited by this where lights is needed in near you without a distracting hot spot.


Both reflector and zoom lens lights have there benefits but one should be mindful of there disadvantages when considering your intended application. Sadly many believe that the zoom lens give you the best of both worlds where in actual fact it under performs in its focused mode. A fix reflector or fix lens makes much better use of the light it has but you can not change it if needed. It is possible to specify that the reflector and fix lens have a uniform beam in flood mode but very few buy such a light.

Zoom lights are probably meant as a convenience, but they are just mediocre at best and terrible at their worst.

Still, gotta love those little sipiks though
Thanks for the info

Sipik cheap and flood to zoom, I like.

Yup. One advantage of zoom lights is that they allow a whole lot of throw in a very compact package…. typically more throw than you could get with a compact reflector light. The downside is that the large portion of the beam that hits the side of the bezel when the light is in spot mode is usually lost. Typically, the smaller the lens and the further the focal point, the more light will be wasted inside the bezel.

A few observations on zoom lights:

1. All budget zoom lights work by having a simple aspheric lens in front o the emitter. Move the lens and emitter closer together for flood mode and increase the distance so the base of the emitter is at the focal point of the lens for spot mode. Most budget lights do this by mounting the light on a sliding sleeve. Some lights have the sleeve threaded so it unscrews. Others have the lens fixed in place, but have the LED star mounted on a moving platform controlled by a turnable ring or even a motor.

2. The closer the lens can retract to the top of the emitter, the larger the lumen output of the light and the wider the flood mode. Ideally, you want the back of the lens almost touching the emitter. Many budget zoom lights don’t allow the lens to retract far enough leaving a useless “flood mode” that feels like you’re shining your light through a toilet paper tube. It is often possible to mod these lights for much improved spill. Anything that lets the emitter sit closer to the back of the lens in flood mode works. I’ve tried all of the following mods, and all work to improve flood:

(a) file down the sides of the body to allow the sliding bezel to retract further.
(b) file down the top of the pill to allow the bezel to retract further.
(c ) add copper or aluminum disks below the star inside the pill so that the LED sits higher up in the pill.
(d) add a shallow plastic reflector inside the pill around the star, to help capture some of the wasted output and direct it through the lens. (gives much improved flood mode with a broad hotspot and eliminates almost all the rings caused by light bouncing around the inside of the pill. Downside is in spot mode you’ll get an ugly halo around the spot.

3. Higher the surface brightess, the better the throw. In order to get maximum throw you need an emitter with high luminance (surface brightness). Think of surface brightness as lumens per square milometer. Smaller emitters tend to have higher surface brightness than larger emitters. However, larger emitters will produce more lumens due to their larger surface area. This means if you want maximum throw in something like an SK68 you should stick to a small emitter like an XRE or XPE2. Switching to larger emitter such as XPG2 or XML2 will usually produce a wider, dimmer spot.

However, because the small emitters produce fewer lumens, if you pick the smallest throwiest emitters, you’ll get a weak flood mode. If you want great flood mode you’ll need a big emitter like an XM-L2… but you’ll get it at the cost of a mediocre spot mode. If you want great spot mode go with an XPE2 … and have weak flood mode. If you want a compromise, go with an emitter in the middle like an XPG2.

4. When performing any mechanical mod that adjusts flood mode or changes the emitter, it may be necessary to refocus spot mode onto the focal point. It may be necessary to add spacers made of bent strips of aluminum or copper around the top of the pill to allow the bezel to extend further, etc.

5. LED Lenser - It’s possible to make a zoom light that has virtually the same lumen output in both flood AND spot modes. This is done by having a carefully engineered lens or lens/TIR with a pocket in the center that wraps completely around the LED in both flood AND spot modes. This requires that the LED be mounted on a raised pillar instead of a conventional flat star. Since all light coming out of the LED is gathered by the lens/TIR regardless of which position the bezel is in, total light output doesn’t appreciably change.

Unfortunately for us modders, the patent on this mechanism is owned by LED Lenser. The only brands to use this system are LED Lenser and Coast (done presumably with license from LED Lenser). No budget lights use this mechanism… even the budget lights that look like LED Lensers don’t use the optics of an LED Lenser…. instead they all use simple aspheric lenses.

6. Wavien Collars -Instead of losing light into the bezel of an aspheric light in spot mode, a small reflector called a wavien collar can be added to reflect that light back to the emitter. This increases the luminance of the die by further exciting the die to emit more light, and by reflection as some of the light reflects off the top of the die into the lens. Wavien Colllars are used in the Deft-X to dramatically increase throw.

I don’t know of any zoom lights using a wavien collar, but see no reason why it couldn’t be done. Mount the LED on a 10mm star on a post, then have the wavien collar attached to the bottom of the sliding bezel/lens assembly. When the lens is retracted for flood mode, the wavien collar would also slide back out of the way around the post allowing for a wide flood … someone on BLF should try making one. :wink:

7. De-doming - one way to increase surface brightness is to de-dome the LED. If done right, this reduces overall lumens (so flood is worse), but increases the luminance so you get a smaller more intense hotspot in spot mode. From what I’ve read, the most effective way to dedome the resin lens on an XPG2, XPE2, or XML2 is to soak it in gasoline and then push the softened lens off.

8. Recoil thrower - most reflectored LED lights mount the LED at the base of the reflector. However, some lights mount the LED on an arm at the front of the light near the lens. The LED is mounted backwards so it faces into the deep reflector. This type of reflectored light is called a recoil thrower and can produce similar or even superior throw to an aspheric. A downside however is that because the LED is mounted on a small arm, it is very hard to dissipate heat so a powerful or overdriven emitter probably isn’t practical.

9. Zoom lights and water resistance - forget about making a cheap zoom light waterproof. In most cases it isn’t practical. Most budget zoom lights work with a silding bezel/lens assembly. Moving the bezel changes the physical volume of the light. If the light is airtight, air pressure inside and outside the light will want to equalize. This will cause the bezel to slide on its own back into the position it was in when the battery tube was sealed. Vacuum action may also cause the light to suck in water past the o-ring if it is cycled underwater.

To insure smooth one-handed zooming operation, small zoom lights should purposely be left not watertight so that air pressure can equalize. This can be done by leaving off one of the o-rings near the bezel.

Advantages of zoom lights compared to reflectored lights:

  1. may have perfectly uniform flood modes with no hotspot.
  2. excellent throw in a smaller package
  3. No spill, so you won’t be lighting up things you don’t want to. Especially helpful when looking at things in spot mode, as the spill from a reflectored light on things in the foreground may blind you to things in the distant spot.

Advantages of a typical reflector light:

  1. Can have both spill and spot at the same time, potentially giving more situational awareness.
  2. Mechanically simpler. Much easier to make waterproof.
  3. May be brighter (more lumens)

i don’t really like zoomed light,once had it and i give it to my grandpa :stuck_out_tongue:

I’ve never been happy with the tints of zoomies.
I don’t know whether it’s the effect of the aspheric lens (?) or what but every zoomie I’ve owned is cool white with a noticeably bluish tint (which I dislike).
I’ve tried searching all over for zoomies that come in (hopefully) 4C tints but with no luck.
What I’d really like is an xml zoomie, 2.8amps (more is better), in a 3C/4C tint.
Anyone know of any?

What is not mentioned yet is the influence of the the beam angle on zoomies, the good old XR-E has a 90deg beam angle which makes the sk68 (together with its quite optimal optical lay-out, which can not be said of most other zoomies) so effective. The most popular leds today are Cree's XP-E, XP-G and XM-L (or their mark2), and the beam angles (angle at which the light intensity has dropped to 50 % of the max) are resp. 110deg, 115deg, 120deg. (or something close to that, too lazy to check it now). So the xpe has a bit less light loss in a zoomie than a xml. However there are some leds that have a narrower angle, the narrowest I know is the Osram SSL80, which has a beam angle of 80 degrees (it has a special shaped dome). These leds perform much better in a zoomie. I have a SSL80 sk68 mod that is doing very nicely, the output zoomed out is very close to the output of a reflector light with the same led, and zoomed in gives 72% of the output of zoomed out, no other zoomie comes close to that. The SSL80 is not as efficient as the latest Cree's but that is more than compensated for when used in a zoomie.

Oh yeah good point.

Aspherics work best when as much as possible of the raw light coming out of the emitter passes through the lens instead of hitting the bezel. The narrower the beam angle the better. That said, a narrow beam angle on a low-output old LED still might not be able to compete with a highly driven modern LED with a wider angle.

Tint is completely unrelated to the aspheric lens. It’s solely due to the emitter the manufacturer chose to put into the light. If you don’t like the tint you can swap the LED in an aspheric just like you can with a conventional light. I’ve done it many times. The tint of an XML2 neutral or ZPG2 neutral looks the same regardless of whether it’s installed in an aspheric or reflector.

not true

take a zoomie w/ plastic lens that has a purplish beam, put in a glass lens, and see it turn the (still terrible but not purple) tint of the emitter whiter

not all plastic lenses have that terrible effect, but many do

My Sipik with a high CRI Nichia 219 B10 emitter shows a bit of tint shift on the margins of the beam .

I believe that plastic zoom lenses do alter the tint .

Hm. I suppose some of the cheap plastic lenses might slightly alter the beam. But not by a huge amount.

I’ve generally replaced the emitters in my zoomies with neutral tint XML2 and XPG2 emitters and the tints look exactly the same as when those emitters are installed in high-quality reflector lights. No hint of green or purple anywhere. And the zoomies I do this with continue to use their original cheap plastic lenses.

I generally change both emitter and lense

but some are much worse than others….

Zoomies have their own advantages and the most significant one is offering relatively better throw than the reflectored lights. The problems with the zoomies we have are probably due to the budget lights manufacturers refuse to make good quality zoomies for some reasons while high quality reflectored lights are very common.

I do notice the blueish or purplish tint in all of my zoomies, from SK68 clone to Romisen RC-C8 and they were ugly and this is another reason I don’t play around with zoomies anymore. Perhaps a neutral/warm/dedomed LED would looks better.

+1. I’ve owned a lot of zoomies and the tint (especially ’round the edges) has always bothered me.
The quality of glass definitely has an effect on tint, and that’s why the properties of optical glass (used in camera lenses) is so critical - and expensive. I figure cheap plastic lenses are even (much) worse in this respect.

The last zoomie I bought was just a month ago and it has this purple-ish tint that irritates me no end. But I can’t complain, since it is a cheapo one that I ordered to use as a loaner :wink:

I'm a bit confused here: It is obvious that a reflector would benefit from de-doming, as more light will be bent by the reflector. But would a zoomie also benefit from de-doming? Or would more light just hit the sides of the host and not be directed through the lens?

Then another question: would de-doming the LED in a LED Lenser light see any increase / decrease?

Dedoming increases the throw and decreases the lumens in ALL led lights. This includes both reflector and aspheric lights. It should also increase the throw in an LED Lenser… but at the cost of worse flood.

Note that dedoming also changes the tint, usually making it a bit warmer.

Yeah those bluish tint are irritating. Nevermind I am not going to purchase anymore zoomies until someone has came out a really nice quality one or one with BIG lens.

You may read DrJones very detail explanation here .
It’s a common misunderstanding that the beam angle of a dedomed LED would become wider and more photon hitting onto the reflector resulting more throw, in fact it is not at all because this doesn’t explain why dedoming works with aspherical lens as well. It’s some kind of internal reflection caused by the dedoming that makes the luminance (aka surface brightness) of the die much higher. It has similar effect with the Wavien Collar.

I had my Dereelight XSearcher (aspherical) de-domed last year. What used to be decent thrower is now almost in the monster-class :bigsmile: :bigsmile:
It also got quite a lot warmer, which is great :slight_smile: