If you’ve ever purchased a light bulb, you’ve probably seen labeling describing its performance. In the days of incandescent light bulbs, many of us used “watts” as the determining factor of brightness. In reality, the brightness of a light bulb is best described by lumens and candela. While the two are related, lumens vs candela are actually quite different. They each serve their own purpose in the realm of artificial light.
No matter the length of day or where we live, darkness is a reality for us all. Luckily, modern technology brought us from the days of candles and gas lanterns into the modern era of lithium batteries and LED lighting. I’m a firm believer in a reliable handheld flashlight as part of your everyday carry equipment. When choosing a handheld, or even a weapon, light; how does candela vs lumens play into making an informed decision to purchase a light that fits your needs?
Candela vs Lumens: What are They?
The definition of candela vs lumens is really a simple explanation. While I’ve put candela first throughout this writing, let’s start with defining lumens.
Lumens
Lumens is the SI unit of luminous flux, equal to the amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candela. If this Oxford definition was brutally confusing, I understand. Let’s put this in plain speak.
Lumens is a measurement of the light’s volume or flow rate. Think of it this way — lumens are the equivalent of how quickly water flows through your tap at home. For example, if you’re washing dishes and only turn on the tap a little, the water flows slowly. If you turn the tap on full volume, more water flows out of the tap in a shorter amount of time. This flow rate is analogous to lumens, except the unit measured isn’t water, but light.
Candela
We’ve defined lumens as the volume of light emitted from a light source. So, in the realm of candela vs lumens, what is candela? In referring to an abbreviated Oxford definition, candela is the SI unit of luminous intensity. Candela measures how intense the light is in a particular direction.
I previously described lumens as similar to how much you turn on your household faucet. In sticking with the same theme, I’ll use the nozzle on a firefighter’s hose to describe Candela. If you’ve ever watched a firefighter operate a firehose, you’ve probably seen them adjust the nozzle. The stream of the firehose can either be a wide spray or a tight stream. The flow rate (e.g. lumens) doesn’t necessarily change. However, the dispersion of the water ejected from the hose changes. This is Candela.
Candela vs Lumens: Why Do They Matter?
When comparing lights, you may look at several factors before purchasing. Elements such as cost, durability, battery life, and size are all important considerations. However, you will want to consider which takes priority in weighing the importance of candela vs lumens.
Lumens
Once again, let’s start with lumens. Lumens determine, more or less, a light’s brightness. For comparison, a 100-lumen light bulb will illuminate a bedroom just enough to see detail. Conversely, an 800-lumen light bulb will brightly illuminate a bedroom and reduce shadows and dark spots. For reference, most household light bulbs are in the 800-lumen range.
When considering a flashlight purchase, it’s important to consider how bright of a light you need. Some lights, such as the Streamlight HL5, provide 3,500 lumens. Is it necessary for your needs? Probably not. A Streamlight Strion LED HL, at 615 lumens, may be more suitable for practical daily use.
There are some fantastic pocket flashlights, such as the Streamlight MacroStream USB, that offer 500 lumens of light in a convenient package. I’ve used this little light’s counterpart, the MicroStream USB, as part of my law enforcement work when reading identifications, taking notes, or searching a vehicle because my hands are full. This light is one example of an overwhelming array of flashlights available in all types, sizes, and price ranges.
Candela
Quite frankly, candela complicates the simplicity of judging a light’s “brightness” based solely on lumens. It’s easy to say a light with more lumens equals a brighter light. This is somewhat true.
You can have two lights side by side with the same lumen intensity but completely different candela. For example, the Surefire X300 Ultra emits 1,000 lumens with 11,300 candela. Surefire advertises the beam distance for this light at 213 meters. Now, let’s look at the Surefire X300 Turbo. This light emits 650 lumens but produces 66,000 candela. As a result, the tighter beam translates to an effective distance of 514 meters per Surefire.
More lumens will undoubtedly produce more light. However, candela determines what is done with that light. If it’s a laser-tight beam, it will cast light over a greater distance and consequently have higher candela. A light with lower candela but just as many lumens will illuminate a greater area but not provide as much distance. Which is better? It truly depends on several factors and what we’re going to discuss next.
Candela vs Lumens: Some Considerations
When looking for a light to fit your needs, candela vs lumens is a scale where your needs may tip towards one or the other. The primary consideration is application. What do you want to use the light for? Weapon-mounted? Handheld? Daily carry? Target identification? Walking the dog? Every situation is unique but there are some considerations relevant to choosing lumens or candela for your light.
Personal Defense
Personal defense lights fall into two categories: handheld and weapon-mounted. For ease of use, I prefer weapon-mounted as it frees up the non-shooting hand if it’s required to perform another task. Furthermore, the non-shooting hand can maintain a grip on the firearm without requiring it to hold a light independent of the gun. Thus, the focus here will remain on weapon-mounted lights.
When weighing candela vs lumens in choosing a weapon light, candela is important if distance is required. Thus, a high candela weapon light is beneficial if you’re using a rifle and anticipate longer-distance shots. For those of us who live in open areas (e.g. the country), a high-lumen weapon light with high candela does a great service to your personal defense package.
For pistols, I prefer a high-lumen light with a wider “throw”. By throw, I mean a wider beam, which translates to lower candela. This wider beam is nice for covering a wide area on a target or clearing a room. Furthermore, the wider beam has less of a hot spot on the target and is less likely to wash out an area. “Washing out” is an issue where the lumens and candela of light are so bright that they overwhelm our eye’s ability to see a spot because the beam produces too much brightness at short distances. This is an isolated issue, but worth noting. Our eyes take time to adjust to changes in lighting. That time is critical to keep the circumstances in your favor if presented with a situation where lethal force may be warranted.
Daily Use
My daily carry is a Surefire E2T-MV Tactician. This handheld light runs on two CR123A batteries and is a compact little package. It’s not the only option, as other great ones exist (like the Streamlight Protac 1L), but is the option I chose. The E2T-MV has an 800-lumen output with 3,200 candela. This light has a very wide beam but lights up targets easily beyond 50 meters. I use it regularly to let my dog outside, check our livestock, or find something I dropped in a dark crevice. For everyday carry, a high-lumen output light with lower candela is a great option.
Many of today’s handheld EDC flashlights offer multiple brightness modes. Streamlight, Surefire, and others have a dual brightness setting on their lights. The Surefire that I carry daily can either be 800 or 5 lumens. The low lumen output is just enough to illuminate where I’m walking at night while I can switch it to the brighter setting if I need to illuminate an area for any variety of reasons.
Finding Your Fit
I have probably two dozen handheld and weapon-mounted lights at home. I’ll openly admit I have a thing for flashlights, guns, and knives. We all have to collect something, right? Nevertheless, many of those lights serve a specific role within my and my family’s daily lives. So, at the end of the day, where will the scales tip for you in considering candela vs lumens?
