Preview – Lumens and Candelas
The Difference to a Degree
When the fuse box in the basement blows, you generally grab the Stanley yellow flashlight, turn it on, and go down to change the fuse. If you are using a flashlight professionally, however, your requirements are a bit more demanding. For instance, in military, law enforcement, private-security, and fire-and-rescue applications, not only do you require absolute reliability, you also need a brilliant light in a small casing that is able to withstand shocks and acute forces. Even if you are not a professional but are simply equipping yourself for a possible emergency situation, a more reliable flashlight could save your life.
Fortunately, a number of manufacturers have stepped up to offer high-quality flashlights for quality-minded consumers. Manufactured out of billet aluminum or high-impact plastics and sporting virtually indestructible LED emitters, these flashlights can take a pounding while providing an astounding amount of light.
When shopping for a flashlight, it is common to run into a few terms that may be confusing to anyone who doesn’t hold a PhD in luminance. Instead of simply going with the highest rating listed on the package- for example, 30, 100, or 200-as your deciding factor, here we will explain what those numbers mean.
Typically, the light a flashlight generates is measured in lumens. A lumen is a measure of the total amount of visible light emitted by the unit. There are a number of methodologies available to measure lumens, and a few different standards, so a flashlight rated at 190 lumens can actually appear brighter than one rated at 210. A lumen measurement does not take into account how wide or focused the light is, but just the total amount of lumens emitted by the device. The divergence, or spread, of the beam can be important as well. For a flashlight used primarily at close range, you would want a wider beam than you would if you were working at a longer one. Flashlights are typically rated at their peak lumen output. Naturally, as batteries wear down, light output will decrease, so when a manufacturer states that a particular light has an output of 200 lumens and lasts for three hours, don’t expect 200 lumens toward the end of the three hours.
Another rating that is coming into common use is the candela. It can be a more accurate measurement, as it takes into account beam spread. For example, a standard, wide-spread, fluorescent light rated at 1,700 lumens puts out about 135 candelas. If that same light is focused into a 20-degree beam, it would have a much-higher intensity of 18,000 candelas. Only a few manufacturers are currently using this rating, so a direct comparison between different manufactures’ flashlights is often difficult. Because lumens and candelas measure light in different ways, there is no direct comparison between the two.
A once-popular term that is still heard today is candlepower. Interestingly enough, it is an out-of-date term coined in the mid-1800s. Simply put, candlepower measured the intensity of light as compared to a candle. Candlepower was replaced by the candela in 1948. Although not totally accurate, the modern interpretation equates candlepower to candela in a 1:1 ratio.
It can be difficult to compare flashlights head to head based on the stated lumen, candela, or candlelight measurement. Because light intensity, beam shape, power stamina, and other factors all come into play when choosing a flashlight, your best bet is to choose a quality one. For this guide, we selected products from LED Lenser, Inforce, Streamlight, and SureFire. All of these units are compact, rugged, and built to last. We were impressed by most of these lights overall; your particular application will dictate which one you may want to purchase.
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