When you are looking for a flashlight, you will inevitably encounter terms such as lumens, candela, and lux. These concepts are essential for determining which light is suitable for your needs, whether for tactical applications, outdoor activities, or professional use. In this article, we clearly and factually explain what these lighting terms mean, what they do and do not tell you, and how to apply them when choosing the right light.
What does lumen mean?
Lumen is a unit of measurement for the total amount of visible light emitted by a light source. It indicates how ‘bright’ the light is overall. This measurement is taken directly at the light source and is now almost always specified according to the ANSI standard. This means that the light is measured under standardized conditions, allowing you to compare flashlights effectively.
However, it is important to understand that lumens say nothing about how far a light reaches. A light with a wide beam may have many lumens but limited range. Conversely, a narrow, tightly focused beam with relatively few lumens may still shine a long way. Lumens therefore primarily indicate how much light the flashlight produces in total, but say nothing about its direction or intensity.
Why wattage is no longer relevant
In the past, the brightness of lights was often expressed in watts. With incandescent bulbs, this was a useful indication, because more watts also meant more light. However, the rise of LED technology has made this outdated. LED lights are much more efficient and use less energy to produce the same amount of light. As a result, the wattage of modern flashlights says virtually nothing about their light output. It therefore makes sense that manufacturers have shifted their focus to lumens as a better measurement.
How many lumens do you need?
The number of lumens required depends on what you intend to use the light for. For close-up tasks such as reading a map, 10 to 20 lumens is sufficient. For simple jobs in and around the house, 150 lumens will get you a long way. If you want to illuminate a path in the dark or search outdoors, you will soon need 500 lumens or more. For tactical use or search operations in the dark, lights producing more than 1000 lumens can be useful. The important thing is that more is not always better, but if you really need that extra output, lights are also available with up to 3000 lumens and 6000 lumens. Using a light that is too bright at close range can actually make it harder to see or temporarily blind you.
What is candela?
Candela is a measure of light intensity in a specific direction. Whereas lumens measure the total amount of light, candela indicates how intense that light is when it is focused and directed at a single point. It therefore says a great deal about a flashlight’s ‘range’. A light with a high candela rating has a narrow, concentrated beam that reaches far, such as the Fenix TK30, making it ideal for situations where you need to see over long distances, for example through fog, smoke, or across a large area.
The higher the candela rating, the better the light can project sufficient illumination onto a specific point at a long distance. This is often referred to as the light’s ‘throw’. Candela is usually measured at a distance of 1 meter or 100 meters from the center of the beam, also taking the shape of the reflector and the light’s lens into account.
The role of lux
Lux is a less commonly used term for flashlights, but it does play a role in the broader understanding of lighting. Lux indicates how much light reaches a particular surface. One lux is equal to one lumen per square meter. Because lux depends on the distance between the light and the illuminated surface, it is a dynamic unit. The farther you are from a surface, the lower the lux value.
For flashlights, lux is therefore less relevant as a specification because users constantly change their distance and angle. Nevertheless, lux is often used in work environments to determine how much light is needed at a workstation, or in standards such as NEN-EN 12464-1 for office lighting.
Lumens versus Candela: what is the difference?
The main difference between lumens and candela lies in spread versus focus. Lumens measure the total amount of light in all directions, while candela measures how intense the light is in one direction. This explains why two flashlights with the same lumen output can perform completely differently in terms of range.
Suppose you have two lights, each producing 1000 lumens. One has a wide 120-degree beam, while the other has a narrow 30-degree beam. The latter will have a much higher candela rating and therefore shine farther, because all the light is concentrated into a smaller angle. This makes candela the better indicator when you want to know how far you can shine, while lumens are mainly useful for determining how brightly your surroundings will be illuminated.
Practical applications and choices
In practice, the right balance between lumens and candela depends heavily on how you use the light. A technician working in small spaces will primarily benefit from a light with a wide beam and modest lumen output. A hunter, security professional, or rescue worker will want a powerful beam with high candela to identify objects at a distance. In tactical situations, a combination is important: high lumen output for overwhelming brightness at close range, and sufficient candela for long-range visibility.
A good flashlight therefore often offers multiple modes: from low output for close-up work to high output with maximum throw. The beam pattern also plays a role. Some lights combine a strong hotspot with a wide corona of surrounding light, giving you both long-range and broad visibility.
Choose based on your application, not just the numbers
Although lumens and candela provide valuable information about a flashlight, it is important to remember that numbers do not tell the whole story. Always consider the complete picture: the beam shape, the intended use, the distance at which you work, and the environment in which you use the light. Do you need to see through fog? Choose a high-candela light. Do you work in a tent or vehicle? A lower output and a wide beam will be more useful.
So do not be dazzled by the highest lumen count on the packaging. Instead, consciously choose the specifications that suit your situation. At NLTactical, we are happy to help you choose the light that best matches your mission.