very light company sells their flashlights by lumens, which makes it the only consistent metric you can use to compare them (assuming they’re telling the truth, of course). But the real question is, how are those lumens shaped? Depending on the flashlight, 500 lumens can look radically different. One will give you a nice view of your whole campsite while another will let you see that bear 50 yards away.
We’ll explain why you shouldn’t pay much attention to lumens and tell you what you should think about when you’re shopping for a new flashlight.
So what are lumens? They’re a measurement of the total amount of light being emitted by a source. It’s more technical than that, but that’s the gist. The key is understanding how those lumens are focused by the flashlight and then matching that up with your needs.
Take a look at these two pictures and tell me which has more lumens:
The first one is 450 lumens while the second light has only 300 lumens. But the second light is concentrating those lumens in a tighter area (often referred to as "throw"), which brightens the center at the expense of the periphery. For the record, the first one is a Petzl Actik Core headlamp and the second a Streamlight TLR-2 weapon light.
This is an example of candela in action. Candela is a term you’ll see on the spec sheets of more serious flashlight manufacturers and it essentially is the intensity of the lumens in a single direction. Again, if you’re a math nerd, feel free to geek out on this (https://www.ledwatcher.com/light-measurements-explained/), but this is essentially what candela are.
Frustratingly, relatively few manufacturers spec and share the candela for their lights, making it difficult to compare. And even if they do, it still doesn’t give you a true picture of what the shape of the light beam is. Sure, if you’re comparing two 1,000-lumen lights and one has 27,000 candela while the other has 40,000, we can conclude that the lower-candela light will have more of a flood-light result while the higher-candela one is more spot. But what if you’re comparing two lights with different lumens AND different candela?
You have better things to do with your time than develop your visualization skills to the point you can picture the beams that result from two different lights. That’s why we actually test, review and share the beam shapes for you in all our reviews!
But before you shop for a new flashlight or even read our reviews, the first question you should ask yourself is...
How am I going to use this light?
The Petzl beam shown above is terrific for walking around a campsite, working on your car, reading a map, etc. But the measly 300 lumens from the Streamlight will generate f-bombs if that gets reflected into your eyes from your brake rotor. And its narrow spread sucks if you’re walking through the woods.
Likewise, a light with multiple power levels is terrific for all-around use, but it’s sure going to suck when you hear an animal growling in the bush, your motor skills turn into slush as your imagination takes over, and all you’re getting out of the light is 15 lumens.
So let’s look at a couple jobs that your flashlight might do for you to illustrate (illuminate?) the differences, starting with self defense.
Scenario 1: You’re snuggled up under your covers and dreaming of sugar plums when the sound of a chair sliding in the other room wakes you up. You grab your Glock and, being a smart, responsible person, your flashlight. A large residential room might be 25 feet wide, so you need a 1,500-lumen monster, right? Let’s find out.
Let’s start with that Streamlight TLR-2 from 25’ away. (And before the Internet safety trolls jump out of their chairs, you should NEVER point a gun at anything you’re not willing to destroy. And if your light is attached to the gun, you don’t yet know if you want to shoot or not, but that’s where the muzzle’s pointing. This is one of the limits of weapon-mounted lights and a lesson as to why you should have a light on your weapon and in your pocket.)
We can pretty easily spot the bad guy, trying to hide behind that palm, so 300 lumens does the trick. Notice again how tightly concentrated those 300 lumens are though (and notice the laser dancing on bad guy’s forehead!).
Let’s see the Petzl Actik Core’s 450 lumens in action:
Not bad! We can see him just fine and the beam spread actually would allow us to see if he had a buddy or two close by, unlike the Streamlight. However, the intensity of the Streamlight in that smaller area (remember candela?) is going to do a much better job stunning and ruining the night vision of the bad guy, so we’ll take the 300 lumens over the 450.
Let’s see what a 1,000-lumen Surefire lets us see (E2D Defender):
Nice and bright, but, to be honest, not a whole lot of difference vs the 300-lumen Streamlight.
Okay, let’s try the big dog, the 1,500-lumen Surefire Scout M600DF:
Whoa! Ain’t no hiding from that! But is it really 33 times brighter than the 45-lumen cheapo LA Police Gear penlight that they threw in the box with some stuff I ordered years ago? Not at in-house distances.
This is exactly why lumens are deceptive. The Surefire Scout has lumens to spare but it’s not as focused as some of its competition, which results in a lot of flood light and less focus in the center. Is this good or bad? It depends on what you need it to do!
If you’re just a normal dude/dudette looking for a light to accompany your handgun or long gun for home defense, lumens and candela don’t matter a lot because the distances are so short. What will matter is how easy it is to use during stress, how long the batteries will last when it’s just sitting around and will it always turn on when you need it to. You shouldn’t care about total lumens or candela or runtime or waterproof ratings or whether Tier 1 secret squirrel operators keep three on their carbines.
We’ll review and recommend home-defense lights in a future article.
Scenario 2: It’s 2 a.m. and we’re freezing our butts off in our tent because we didn’t read AdventureCo’s sleeping bag review (link). Suddenly we hear a noise and we don’t know whether it’s a bear, a squirrel or Carl sleepwalking.
We fumble around for a flashlight, pretend we’re silently unzipping the tent flap, and 45 yards out we hear the noise again. Now that penlight isn’t so helpful:
So we grab our headlamp and crank it up to the full 450 lumens:
Spreading those lumens out wide is great when we’re setting up camp, but not so much when there might be danger farther out.
Maybe that Streamlight?
Now we’re getting somewhere! We can see it’s a person, but we still don’t know if it’s Carl or a bad guy. Then we remember we brought a Scout 600 and we grab that:
Bad guy! Pew pew!
And now we see the lumen vs candela issue play out with the Scout. While inside the house the spread of the beam didn’t matter, once we’re talking longer distances, it does. Yes, we can tell it’s a bad guy (and it’s bright enough to at least disorient him), what if he’d been 70 yards away? You don’t want to shoot Carl, no matter how bad he snores.
Goldilocks would find it infuriating, but there is no single flashlight that will be “just right” for all your needs. It comes down to how and where you’re going to use the light, so you might as well figure that out, plan on buying multiple lights and prioritize your spending based on the urgency of your needs. And based on those needs, look at candela before lumens.
We hope you’ve found this illuminating (ha!). Any feedback or questions, drop us a note. We read everything you send us!