So, you want to buy a flashlight? In the world of flashlights there are 2 ways to go. First is to walk into a department store and grab the first thing you find on the shelf, trusting the marketers who made the packaging flashy and appealing to the eye. This is generally considered a big mistake for any consumer product! Usually flashlights bought in this way wind up in a kitchen drawer as "dead battery holders". The other is to really think about your purchase, do some research, and buy a good light that suits the needs that you have. This is by far the best way to avoid disappointment and to find a personal lighting instrument that you can rely on and depend upon for many, many, years.

In this article I hope to help the general consumer gain a little knowledge about what they may be getting into, some of the pitfalls, and the myriad of different options currently available on the market. You may be stunned to find out about the number of various styles, designs, and capabilities of the latest generation of personal lighting devices available.

Intended purpose

The first thing you have to think about is "What am I going to use this for?" I don't mean just for 'seeing in the dark'! Are you going to use this on the job, in an industrial setting, camping, diving, search and rescue, caving (spelunking), general household use, etc. Based on what the flashlight will be used for you can decide what features will be needed and which would just be additional cost or bulk. For example, if you were going to use a light for general household tasks, it may be advantageous to get an alkaline battery powered incandescent that runs on D cells since size and weight are not going to be a big factor if it just sits in a corner until it is needed. If you are going backpacking, you will probably want a small, lightweight flashlight that uses LEDs for efficiency so you don't need to carry lots of additional spare batteries in your pack. As I go through the various features available in lights these days I'll try to point out the benefits of each so you can make a more informed decision about your purchase.

Headlamp or Flashlight

Hand held flashlights are great for brief tasks, but if you are in an extended power outage, or setting up camp, nothing in the world beats a headlamp for hands free lighting. If you can get over the fact that you'll look like a miner or a geek, you won't regret it. Trying to set up camp with one hand is just about impossible. So are most daily tasks in the dark. I always thought headlamps were goofy until we had the power out for an extended period. Now I make sure I have one ready and fully loaded with batteries for each family member.

Body Materials / Finishes

The material that the body of a flashlight comes in is sometimes an important consideration. Generally you will find 2 types of body materials: Aluminum and Plastic/Polymer.

Aluminum

Aluminum bodies are found on a variety of "better" lights, the most common example of which is the Mag series of lights. The aluminum bodies are fairly durable and although subject to deformation from sharp impacts, they can usually take a beating. Most aluminum lights come in a standard flashlight cylindrical shape since the shape is the easiest to make when machining aluminum. When looking at an aluminum light consider the finish. There are 3 primary types of finish on the market today. 'Powder coated' is considered the weakest finish. This type of coating is paint that is bonded to the metal with heat. It will protect the metal from corrosion, but it can also scrape off. The next strongest finish is anodize type 2. This is what you will find on a common Mag light. The finish is actually the result of an electro-chemical process that forms a layer of oxidization on the surface of the metal, which is then chemically colored. The process can produce a wide variety of metallic finish colors. Anodize will wear off and ding, but it holds up pretty well to general and some rough use. Anodize type 3 is the hardest finish available for aluminum. Like anodize type 2 it is actually the result of an electrochemical process but is very, very hard. Type 3 will take a very serious beating and will often wear away other metals before it takes damage. Powder coating and anodize type 2 finishes are good for most folks and tasks. If your light will be subject to a lot of bangs/dings/friction, consider a type 3 anodize finish. Some Surefire and all Arc brand flashlights use type 3 anodize.

Plastic / Polymer

Lights made with plastic or polymer tend to come in a greater variety of shapes since the plastic can be molded rather easily into nearly any shape desired. You'll find flat ones, round ones, and nearly everything in between. Plastic and polymers come in a large variety of grades and types - far too many to mention here. Generally the more expensive lights are made of better quality grades of polymers that can take a beating. There are a number of advantages of getting polymer lights. Polymer lights are the same color all the way through the body, so nicks and scrapes don't show up as readily as on aluminum lights. Polymer lights are naturally resilient and tend to flex instead of bend or dent when subject to impact or drops. They can be found in both very dull colors and very bright fluorescent colors, so if either discretion or visibility is your concern, you can find a light that suits your purpose. For many purposes it may be wise to get a light that is brightly colored and easy to identify so that if it is placed down somewhere it is easy to spot against the background. This is especially important when hiking / backpacking / camping.

Bulbs

There are several types of bulbs that are available for flashlights. Bulbs can be broken down into three main categories: Incandescent, LED, and fluorescent.

Incandescent bulbs produce light by heating a tiny, fragile filament almost to its melting point. The filament glows brightly in protest, producing usable light. As the batteries lose power, the filament cools and produces light that is more and more yellow until it finally goes out.

LEDs produce light by taking the energy of the batteries and turning most of it directly to light. LEDs tend to be very efficient at lower light levels and do not turn yellow as the batteries are depleted. Instead they just produce less light, but of the same color.

Fluorescent bulbs light an area by causing a filament inside to emit energy that causes a surrounding layer of phosphorescent material to glow. The light from these bulbs is a soft area light and cannot be focused into a beam.

Incandescent bulbs

Let's take a quick look at the construction of incandescent bulbs out there and the merits of each.

"PR based" bulbs are the common flashlight bulbs you find. They have a metal base with a contact at the bottom, a metal collar at the top of the base where the glass envelope is attached, and a filament in a glass capsule. These bulbs are usually held in place by the metal collar and do not move if dropped or impacted. However, drops and impacts will sometimes cause the hot filament to flex and break.

Bi-Pin bulbs are simply a glass capsule with the filament inside and two pins coming out of the base of the glass bulb. These bulbs are pressed into a socket and rely on the socket to hold them in place. If the socket does not hold the pins tightly the bulb may pop out of its socket if the light is dropped on its face, leaving the bulb rattling around inside the reflector. Repeated bangs can loosen the bulb and cause the focus of the flashlight to change as well. Usually opening the light and a gentle press with the fingertip will push the bulb back into place if it moves. Because they lack the metal base they are usually rather small in size and therefore it is very easy to carry spares or to fit a spare right in the flashlight itself. These bulbs are found in the Mini Maglight and the Streamlight Scorpion.

Lamp assemblies are usually the most secure of the bulbs. Generally these consist of one of the two types of bulbs listed above that are permanently mounted in an assembly or carrier that is installed into the light. Some lamp assemblies only have a carrier for the bulb and some have the reflector attached. These tend to be more expensive than the above two. Surefire lights use complete lamp assemblies.

Regardless of the type of bulb assembly, note that all incandescent filaments can be subject to breakage if dropped or subjected to impact. It is the nature of the beast. White hot tungsten does not react well to being banged around.

All of the above bulbs come in a variety of chemistries.

"Standard" bulbs are bulbs that have nothing but a vacuum inside the glass capsule around the filament. These are the most inexpensive and produce the least light of the bulbs available.

Krypton bulbs are by far the most common. These tend to be the "regular" flashlight bulb that you get with most inexpensive lights. The glass envelope surrounding the filament is filled with krypton gas, which helps the filament produce more light.

Halogen bulbs are brighter than the above two and tend to draw more electricity. They also seem a bit more durable. The glass envelope is filled with a mixture of halogen gasses, which help preserve the life of the filament and make it brighter.

Xenon bulbs have the glass envelope filled with xenon gas. Like the halogen and krypton bulbs, this helps lengthen the lifespan of the filament and produce more light. In the case of xenon bulbs, however, the light produced is a very pure white light - much more so than any of those above. Xenon filled bulbs are about the best you can get for common incandescent flashlights.

HID bulbs, or High Intensity Discharge bulbs are a little different from incandescent filament bulbs. They produce light my making a tiny spark between a gap in a pair of electodes to heat a gas in the bulb to a temperature where it incandesces (emits light). These are found in some high end dive lights and some military lights. These are extremely bright. This is the type of bulb found in those "bluish white" car headlights. (By the way, if the headlights on a car give off really blue or bluish green light, those are just regular bulbs coated with a tint in a pathetic attempt to look like the expensive HID headlights.)

LED bulbs

LEDs are fairly new on the scene of flashlights and they are really taking off. They tend to be much more energy efficient than incandescent bulbs, running 5-10 times as long on a set of batteries, and they won't "blow" if subjected to impacts. They have very long lifespans, lasting into the thousands of hours in normal use, unlike incandescent bulbs, which generally tend to fail after 5-20 hours of use. However, they are not as bright as incandescent bulbs, but that is changing.

LEDs are available in a variety of different colors - nearly every color of the spectrum. Let's take a quick look at some of the various colors and what they are used for.

White: General all around best color for our vision. Give excellent color recognition. All the rest can be considered "special purpose" lights and do not allow color recognition at all. Essentially using any of the colors below is the same as seeing things in "black and white".

Red: Night vision preservation at low lighting levels. More info here.

Amber: Focuses well in the eye and is usually a very "comfortable" monochromatic light to use

Green: Doesn't cause military night vision equipment to overload or "bloom" when used. Does NOT preserve normal human night vision despite reports otherwise.

Blue: Good for hunters following the blood trail of wounded game. The blood shows up as solid black in this light.

Cyan: Brightest of the monochromatic colors. Some people just like the look of it.

There are 3 primary types of LEDs you'll find in flashlights.

3mm LEDs are tiny LEDs that are used in some very small lights. Due to their size they produce the least light of the LEDs.

5mm LEDs are the most common LEDs to find. They have been used in specialty lights for some time and are now working their way into flashlights that can be bought at common department stores.

High Power LEDs are very large LEDs that run hot. These LEDs produce light that is starting to rival incandescent bulbs. Surefire and Arc Flashlight use these LEDs in some of their lights. These LEDs includ the Luxeon brand as well as many others. Luxeon have historically been the most popular and they come in a variety of types and Wattage consumption.

Luxeon I (Luxeon Star, 1 Watt) Low Dome LEDs: These are fairly bright, but there has historically been a lot of variation in the tint of the LEDs. Some appear greenish, some bluish, some purpleish. Beam pattern is generally a hollow cone of light. Special optics and reflectors correct this to produce a nice spot of light.

Luxeon I (Luxeon Star, 1 Watt) High Dome LEDs: Output similar to the Low Dome LEDs but light pattern is much more even. These can be focused into a tighter beam in general than the Low Dome Luxeon due to the shape of the epoxy capsule around the LED.

Luxeon III LEDs (3 Watt): Always "high dome". These are really very robust Luxeon I LEDs which can handle much more current and can produce more light.

Luxeon V LEDs (5 Watt) are very bright but require considerably more power than the Luxeon I and III LEDs. These tend to run very hot and need additional heatsinking to protect the LED from thermal breakdown. Output rivals and surpasses that of many common incandescent flashlight bulbs, but the size of the emitter often results in a slight hollow spot in the middle of the beam.

Luxeon K2 LEDs (7 Watt) are the next generation of Luxeons and designed to run at around 6-7 Watts. As of September 2006, these are just starting to appear on the market.

At the end of 2006 / beginning of 2007 two new High Power LEDs have appeared on the market. The Cree XR-E and Seoul P4 are both about "3 Watt" rated, but are about double the efficiency of Luxeon "3 Watt" LEDs. (By the way, wattage is a measure of power consumption, not light emission). This means that you can have either the same brightness as the Luxeon with about double the runtime, or about double the brightness with the about same runtime. I'm sure the technological advances in the industry will continue this trend of increasing efficiency over time.

Single 5mm LED lights tend to produce plenty of light for close tasks in complete darkness and last a very long time on a set of batteries. The CMG Infinity and the Arc AAA are examples of this application. Multi 5mm LED lights produce a wide flood of light and also tend to last a long time between battery changes. This type of light would include the Tektite Expedition with 7 LEDs, the Lightwave 3000 and 4000 with 7 and 10 LEDs respectively, and the Streamlight 4AA LED with 7 LEDs.

If you are looking for a light that will produce modest amounts of light for very long periods of time, consider 5mm LED lights. LED lights with a number of 5mm LEDs will produce a very good amount of light for a very long time. Remember too, that dropping an LED light will not blow the bulb, so they tend to be very reliable sources of light. The primary disadvantage of 3mm and 5mm LED lights is that the light cannot be easily focused into a tight spot and therefore generally cannot light up a subject at any distance from the observer.

Luxeon LED lights can be focused very well using special manufactured optics or reflectors which causes the light to rival common incandescent lights, and yet retain some of the advantages (long life, doesn't blow) of the LED lights. However, since they put out much more light than their 5mm LED counterparts, do not expect the super long battery life that the former can achieve. All things being the same, brightness and battery life are in inverse proportion to one another. You have to give up one for the other. The Elektrolumens Blaster 3P is a great example of a Luxeon I LED light that is very bright and the Surefire L4 is an extremely bright Luxeon V light.

There are some new high powered LEDs out on the market now, including the Nichia Jupiter and the Nichia Rigel.

Various overseas companies are also making some other "High Power" LEDs as well. Be warned, some of these "high powered" LED bulbs are not the same quality nor as effective at producing light as the name brand LED bulbs. Be cautious of very low priced LED lights. Remember, you get what you pay for.

In year end 2006/early 2007, both Cree and Seoul Semiconductor came out with new 3 Watt rated LEDs (XR-E and P4, respectively) which just about double the efficiency of high output LEDs. This means that they can either run about twice as long as the then current Luxeon brand 3 Watt LEDs using the same power source, or run about twice as bright with the same runtime. These new LEDs can run brighter and longer in 6V applications than "high powered" 6V incandescents like the Surefire P60 lamp flashlights (G2, C2, M2, 6P, G2Z). These new LEDs essentially both catch up with and surpass tradidional incandescent bulbs used at these voltage levels. See the Huntlight FT01-XSE, Lumapower M1, Amilite Neo T5 and Fenix P3D-CE for examples. This marks a major turning point in LED technology.

Fluorescent bulbs

Fluorescent bulbs are used for area lighting. There are two types currently on the market: Compact Fluorescent Tubes and Cold Cathode Fluorescent Tubes (CCFT). Compact Fluorescent Tubes are not as efficient as CCFT, but both produce nice even lighting for an area. Light from these tubes really cannot be directed very well and are not sufficient for lighting anything but the immediate area around the flashlight.

Batteries

Batteries can be broken down into 3 basic types: Rechargeable, Alkaline, and Lithium. The size (capacity) and type of battery you choose will be directly related to how you use the light. Let's first take a look at the different battery sizes available.

Battery sizes:

AAAA: Very thin cylindrical cell. Not much power capacity, but allows for very thin flashlights. Used in some lasers and the Streamlight Stylus LED pocket light.

AAA: Small cylindrical cells. Decent power capacity for less powerful lights. Good for headlamps where the batteries sit on the front of the head, such as the Eveready LED or the Streamlight Trident. Also good for small keychain or pocket lights such as the Arc AAA or the Princeton Tec Attitude or Impact 2.

AA: Cylindrical cells. Good power capacity. The most common battery you can find. This is probably the best mix of size, power capacity, and price you'll find for small flashlights, both LED and incandescent.

C: Larger capacity cylindrical cells. Lights based on these cells tend to fit well in the hand of most users. Same height as AA cells, but larger in diameter.

D: Largest of the common batteries with the highest capacity. Also the heaviest. These tend to be used in bigger lights or where runtime is a major consideration.

9 Volt: Square cells with the same capacity as AAAA batteries, but at a higher voltage. Used for low-drain applications including the Palight single LED light.

Lithium 123: High output "camera" batteries that produce 3 volts each. Very lightweight and produce very high currents. Used in lights that draw lots of current, such as Surefire. Before using lights that utilize this battery type, you may want to be aware of some precautions since they can burst violently if used improperly.

Lithium AA: Can be used in place of Alkaline AA in many cases, but not all. Very lightweight and also can produce high current if necessary. Great for backpacking applications due to their weight.

Lithium Coin Cells: Flat cells about the size of a nickel or quarter that are commonly used in keychain LED lights such as Inova Microlight or Photon 2. Not much capacity at all, but very small.

More info here.

Battery types:

Rechargeable: Come in a large variety of sizes and are usually built in to rechargeable flashlights. Rechargeable lights are best used in applications where the light will be used frequently for relatively short periods with time to recharge between uses. Great for a general household light since they can be left in the charger and you know it will always be ready for use.

Rechargeable Nickle-Metal-Hydride (NiMH) cells can usually be used in place of alkaline batteries, but sometimes with reduced runtimes and brightness. (Flashlights designed for recharging that include the rechargeable batteries built in will have bulbs matched to the voltage of the rechargeable cells inside.) If left in the flashlight unused, rechargeable cells tend to lose their charge rapidly over time (dead in 1-2 months). This is known as "self discharge" and is a common problem with NiMH, and other, rechargeable cells. As of 2006, several companies including Titanium (Power Enduro), Sanyo (Eneloop), and Rayovac (Hybrid) have developed "low self discharge" NiMH rechargeables which hold about 80% of their charge for over a year without charging if left unused and are fully charged right out of the package.

Lithium Ion rechargeable cells are coming on strong in the marketplace right now (2006). Flashlights purchased with Li-Ion rechargeable cells are designed for their use and they can provide very high outputs at very low long-term operating costs, but lights using these cells tend to be more expensive. As a result there is often a tempation to retrofit a current light to use these cells. If you decide to retrofit a current flashlight with Li-Ion rechargeable cells, you should make yourself aware of some dangers in doing so.

Alkaline: The most common battery formulation to date. Alkaline batteries work best in lights that draw low to moderate current, which includes most common lights. They have a shelf life of up to 7 years. During use they will deplete, rapidly at first, reducing the light output from a flashlight over time. They are available almost anywhere. They do not hold up well in cold weather.

Lithium: Made of a lithium metal formulation, these batteries tend to be able to produce higher currents than alkaline batteries and are not affected by cold weather as much as alkaline batteries. Because they use lithium metal, they are very lightweight, to the point where some waterproof lights float with lithium batteries inside. The only "common" sized battery you will find with a lithium formulation is the AA made by Energizer. 123a lithium batteries commonly are used in high output, short run incandescent lights. Lithium batteries are more expensive than alkaline batteries.

Lenses

In common usage, the piece of glass or plastic in front of the reflector is called a "lens". It's purpose is usually only to protect the bulb and reflector from the environment rather than actually changing the shape of the light from the bulb. It is therefore better called a "window" than a "lens" since light passes though it unaffectted. A true "lens" shapes the light and some lights do use a true lens to change the shape of the beam. Some lenses are very complex, such as the Inova TIR (Total Inernal Reflection) lens which captures almost all the light from the bulb and shapes it in a very specific way. Throughout this site, we use the common usage definition of the word "lens" when talking about flashlights.

Lenses come in a variety of materials. Most of the time the lens at the end of a flashlight is plastic. Some flashlights use Lexan - a clear plastic that will not shatter and is temperature resistant. Others use glass of various sorts, including Pyrex. Glass lenses are usually found in high output flashlights that produce a lot of heat. Plastic lenses would be subject to melting under those conditions.

The Princeton Tec Impact uses a single LED behind a focusing lens that allows the LED to produce a spot of light. Although not very bright, it does allow the LED to be used at a moderate distance, unlike most other single LED lights.

Reflectors

The purpose of the reflector is to gather light that would otherwise be projected to the sides and instead project it forward, out through the lens. Reflectors may be plastic or metal, depending upon the heat resistance needed inside the head of the light. Basically, there are two types of reflectors: Smooth and Textured.

Smooth reflectors

Smooth reflectors have a shiny smooth surface that surrounds the bulb. This allows for a very bright spot of light to be sent from the light. Smooth reflectors produce the tightest and farthest-reaching beams. This works well if the bulb is properly placed in the reflector. However it the bulb is too far forward or too far back, rings of light and dark spots appear in the beam pattern.

Textured reflectors

Textured reflectors use facets or a rough appearance to smooth out the rings and dark spots produced by smooth reflectors. The light will not produce as tight of a beam as one with a smooth reflector, but the light is well distributed. Many "better quality" lights use reflectors that are textured. If the quality of the beam is important it may be worthwhile to investigate textured reflectors. More info here.

Seals

The seals in a light are going to keep the environment out, allowing for greater reliability of the light. Depending on the tightness of the fit of the seal, a light may be water resistant, waterproof, or dive capable. For use on a boat, it may be a good idea to look for a floating light in case it gets dropped overboard. Seals are usually found between the lens and the head of the light, between the head and the body of the light, and between the tailcap and the body. Most commonly the seals in a light are o-rings or gaskets.

O-rings

O-ring seals are simple rings of rubbery material that sit in a groove at the head or tail of the light and create a tight seal when the head/tail is attached. O-rings are commonly found on cylindrical lights and depending upon the size and tightness they can allow a light to withstand significant water pressure. The Princeton Tec Tec40 is a dive capable o-ring sealed light.

Gaskets

Gaskets are usually found on irregular shaped lights or lights with irregular shaped openings. The gasket is pinched between 2 parts of the light and held in place by the fasteners between the two parts. The Eternalight Ergomarine uses a gasket between its two halves. Gaskets can work just as well, and sometimes better than, o-rings.

Both gaskets and o-rings should be kept lubricated. Rub them with a light coating of silicone grease. Although lots of "specialty" O-ring lubricants are available, a tube of common dielectric silicone grease from an automotive store is inexpensive and works as well as anything. Don't use petroleum based products on the seals, as some seals are damaged by petroleum products.

Switches

There are so many different switches I'll only mention a few of the common ones here. The type of switch is again dictated by how you want to use the light.

Bezel twist: Very common type of switch. Twist the bezel for on/off. This type of light usually requires two hands, but many are more water resistant than others since the bezel is the only opening in the light. The bezel is usually removed for battery changes. Example: Princeton Tec Tec40

Side click switch: Also very common, found in some Mag lights. Allows for one handed use. Can be made water resistant with rubber seals.

Tailcap Click: Similar to the side click switch. Usually operated with the thumb. Example: Streamlight Scorpion

Tailcap twist: A bit less common - twist the tailcap for on/off. May be combined with a momentary tailcap press switch. Example: Surefire E2

Membrane press: A plastic membrane covers the switch. Press the membrane to activate the switch. This allows the switch to reside under the surface of the light's body. Example: Eternalight.

Magnetic Reed: The magnetic reed switch has 2 parts. A magnet attached to a sliding switch outside of the light and a glass encapsulated reed on the inside. As you slide the switch the magnet moves into a position where it attracts the little reed and closes a circuit. This type of switch allows the light to be completely sealed - no opening is needed. Example: Nightstar 2.

Side slide switch: Common in less expensive lights. Very hard to waterproof. Example: Eveready Economy Light

Circuitry

Circuitry? In a flashlight? Yup, you bet. Some flashlights have circuitry to allow them to do a variety of functions while others have step-up or regulator circuits. It all depends on what you need! Usually you'll find special circuitry only in some LED lights, but a few incandescent lights use circuits as well.

Function circuitry: This circuitry allows the light to perform a variety of different functions such as dimming and blinking. The Princeton Tec Eclipse is a keychain LED light that you press the on off switch once for bright, twice for medium, three times for dim, four times for slow blink and 5 times of fast blink.

Step-up circuits: These circuits boost the voltage from a battery or batteries to run a bulb at a brighter than expected level. 5mm LEDs require 3.6 volts or more to operate properly. The step-up circuit in the Arc AAA and Infinity Ultra allow the single LED lights to work on only one 1.5 volt battery by boosting the voltage.

Regulator circuits: These are the most desirable of circuits. These circuits regulate the voltage going to the bulb so that light output is constant throughout the battery life - a flashlight that doesn't dim until the very end of the battery life. The Opalec Newbeam 3 LED light uses just such a regulator. The Surefire A2 is one of the few lights that uses a regulator for an incandescent bulb.

Lies, Damn Lies, and Marketing

The last thing I would like to leave you with is this: Let the Buyer Beware! When you read the package about a product, remember that the material you are reading was put there by marketers who have only one purpose in mind: to separate you from your money before someone else does.

If the light claims to last thousands of hours between battery changes, can take a 44 caliber bullet without breaking, or will still work if submerged to depths that will crush a whale, don't believe it. Instead visit our Reviews pages and read what we think of the lights. Also visit the pages of our esteemed reviewer colleagues such as Craig at the LED Museum or Chris at TorchReviews, or come visit all of us at Candlepower Forums where we have a specific forum dedicated for members to post reviews of their own. We all do our best to give honest reviews and help you, the buyer, make good decisions about lights you may want or need.