What's the Difference Between Lumen, Lux, and Candela? 

Everyone looks for the brightest headlight option when they are buying new ones. Even though many brands assert that they are the most colorful, we shall define "brightest" more clearly today. Despite the brand's 20,000 lumen claim, numerous scientific aspects might influence the actual light output. If you stay with us for a little while, you will quickly become an expert in comprehending brightness.

Lumen, Lux, and Candela are the concepts we will discuss to comprehend the science underlying lights and what produces their brightness.

What is LUMEN?

The light source is the primary focus of lumen measurement; LED lights are one example. The amount of light emitted by the LED chips is measured in lumens. When purchasing new lights, this is the term that most people are familiar with. But this is the poorest approach to determine a light's brightness. A lumen, by definition, is a unit of measurement for luminous flux, which is the entire amount of visible light that a light source emits. Don't worry, even though that seems scientific. We'll simplify this explanation as much as we can.

An instrument known as an integrating sphere is used to measure lumens. It would be positioned inside the sphere to measure the brightness that the bulb emitted precisely. Calculating the lumen is simple because light is trapped inside the sphere from all directions. However, 360-degree sphere technology is not used by your headlight. "Doesn't that mean the bulb with the highest lumens will be the brightest bulb overall?" is a question you may be asking yourself now. Lumens do not quantify the interaction between the headlight's optics and the bulb itself. This implies that even if the bulb has 20,000 lumens, only 5,000 may be genuinely usable light you can see while driving. To help you visualize, let's say you have turned on an LED lightbulb.

The lumen measurement would be determined by measuring the total brightness emitted by this lightbulb. Each type of light source produces a specific number of lumens, regardless of whether we are discussing LED, HID, or halogen. After the bulb is inserted into the headlight housing, the optics are what lighting enthusiasts are interested in.

In this instance, the OEM reflector bowl's reflective surface will serve as the optics. These optics produce Candela and Lux using the lightbulb's lumen output. The usable light levels of different lumen-rated bulbs in the same headlight vary. In our lab, we tested this using a variety of H11 bulb types and styles. You can view our H11 testing video by clicking this link. Examples of highly rated lumen lamps with extremely low lux ratings and vice versa are shown in this video. It turned out that several of the lumen bulbs with lower ratings had greater lux ratings. It all concerns the interaction between the optics and the light source.

Inside the headlight system, optics are more than just reflectors. An LED chip would be located behind each projector if you were to dissect an LED projector headlight, like the Morimoto XB LED headlights. This LED chip has a lumen rating, but the light output will alter once it is mounted to a board, placed behind a projector, and shines forward on your car. We also measure Lux for this reason.

What is Lux?

The SI unit of illuminance, or Lux, measures the amount of light flux dispersed over a specific area. This phrase informs customers of the actual, measured brightness at a certain distance in the lighting sector. This implies that testing must occur in a controlled setting because different lux ratings can be obtained using various instruments, walls, and meters. Using the same testing setting and the same testing meters is the only method to get accurate lux values.

At Ledlightjeep, we display a percentage change using lux readings. The OEM headlight and aftermarket light output will be compared when we finish the lux testing in our studio. In this case, we measured the beam pattern on a wall 25 feet distant that was produced by the housing and bulb combination. From this vantage point and distance, we can see how much of the bulb's lumens are being used and converted into a useful beam pattern by the headlight housing. We identify the controllable variable by first measuring the OEM headlamp. We start the testing procedure as soon as we have the controlled variable.

Various aftermarket light sources, like bulb replacements, are used in the OEM headlight unit as part of the testing procedure. The new lux values from the aftermarket light sources will be measured. We will be able to compare our tests' outcomes after identifying the changing variables. We can show a difference in Lux to ascertain which is brighter if we conduct our tests in the exact location within our controlled environment.

Lux has the drawback of only calculating brightness at a specific point in time. Lux needs to be computed at the beam pattern's maximum intensity location. However, improper placement of the lux meter can significantly alter the readings. It would be inaccurate to measure the actual brightness if you moved the meter forward even an inch because it would pick up an additional 100 lux readings. Lux is therefore only helpful for comparisons in a controlled setting. What would happen if you wanted to compare bulbs at various times?

In conclusion, the bulb has lumens, and the Lux is what we can measure when it is placed in a headlight. In general, candella measurements are the most effective for comparing two items.

What is Candela?

Assume that we are testing an LED bulb 25 feet from the wall in our controlled test environment. When you measure your lux meter, you are reading the candela rating at that specific location. It would be at 25 feet in this instance. But this is just a small snapshot. We must consult the Lux testing at particular distances to comprehend the candela rating. Factors, including beam pattern, quality, and value, can influence the overall candela rating. The ideal comparison rating is candela if you're all searching for maximum brightness. Lux is the product that has the ultimate peak intensity, if you're interested. Candela will be used to assess the light source's total brightness. Let's use the Morimoto 4Banger LED pod lights as an example. Each of the LED chips within the pod has a unique luminescence rating. The lux rating measures this light output at a specific location in space.

Nevertheless, candela calculates all of the light generated by the pod. Regardless of the distance during testing, the candela rating will remain constant. The candela rating won't change from five to twenty-five feet.

conclusion

You can confidently compare your lighting changes now that you know the difference between lumens, Lux, and candela. To avoid being duped by other lighting companies, it is crucial to understand these phrases. Consider the lux and candela ratings that an LED bulb with 20,000 lumens will produce the next time you see someone promoting it. Even while 20,000 lumens may seem like a lot of light, it won't help if your headlight's optics aren't correctly used. Compatibility between the light source and optics is crucial for producing a street-legal beam pattern with low glare.

To ensure that you, as a customer, are confident with your lighting choice, the Ledlightjeep staff takes the time to get the car in, do the testing, and perform all the labor-intensive tasks. We outline exactly what to anticipate when making a new purchase. Our HR-tested items will be the best choice for your car thanks to this testing.

We hope that clarified any confusion you may have had regarding the distinctions between candela, lumen, and Lux. Check out our video on the distinctions between Lux, lumen, and candela if you prefer to learn visually or watch this explanation.