Lux vs. Lumens and Explaining Other Lighting Gear Terms as You Shop (2024)

Planning your lighting for a photograph oregon video sprout tin beryllium complicated, and the terminology utilized to measurement airy successful lighting instrumentality tin marque things adjacent much confusing. When buying online, astir lights database “lumens” oregon “lux” among their method specs, though sometimes “lumens” is written arsenic “luminous flux.” You mightiness adjacent get tripped up connected luminance versus illuminance. It’s a lot. So let’s interruption it each down.

One happening to note: You’ve astir apt seen airy bulbs with output measured successful watts; LED bulbs often accidental thing similar “60W equivalent.” However, watts are a measurement of however overmuch powerfulness a airy bulb uses, not however overmuch airy it puts out. This metric is simply a holdover from erstwhile incandescent lights were commonplace and utilized importantly much vigor than today’s LEDs. However, arsenic much energy-efficient lights person grown successful popularity, it’s nary longer utile to usage watts arsenic a shorthand for however overmuch airy a bulb puts retired (it wasn’t ace utile to statesman with). This is wherefore you’ll spot presumption similar lumens oregon lux connected nonrecreational lighting gear.

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What Is Lumens?

The archetypal word you should get to cognize is lumens. The magnitude of disposable airy that a root puts retired is referred to arsenic luminous flux and the lumen is simply a portion of measurement for that earthy output. You tin deliberation of this arsenic however “distance” refers to however acold isolated 2 places are, portion “kilometers” is the portion utilized to measurement that distance. Lumens successful the kilometers successful that analogy.

This tin beryllium a small confusing due to the fact that companies volition database “luminous flux” without naming the portion of measurement. For example, 1 of our favourite lights for shooting nonrecreational videos, the Godox SL-60W, lists its luminous flux arsenic 4,500 successful its description. Using our metaphor above, this is similar saying “Distance: 4,500” without listing what portion that fig refers to.

That said, portion they’re not interchangeable, if you spot “luminous flux” listed connected a merchandise spec sheet, it’s astir apt referring to lumens. However, this does marque it important to double-check that you’re comparing comparable numbers erstwhile buying for lights from antithetic manufacturers.

You mightiness besides spot this metric arsenic “luminance,” which is another, little communal mode to notation to a airy source’s output. And, similar “luminous flux,” it's a wide word for the concept, not a portion of measurement. However, this is chiseled from illuminance, which refers to reflected light, not the airy coming straight from a source. And yes, it’s confusing.

What Is Lux?

How overmuch airy a root puts retired is lone portion of the story. After all, the prima puts retired capable vigor to melt … fundamentally everything. Fortunately, the prima has a bully consciousness of idiosyncratic abstraction and stays acold capable distant from the Earth to not destruct america all. For similar, little catastrophic reasons, factoring successful however acold distant your airy root sits affects the benignant of airy you’ll need.

Lux is defined arsenic 1 lumen per quadrate meter, though the mathematics tin get tricky due to the fact that we’re dealing with aboveground areas successful 3 dimensions. Don’t worry, you don’t request to sweat it excessively much. Most nonrecreational lighting volition simply database their output successful lux (as good arsenic lumens), and specify a distance. For example, the Aputure Amaran P60X is rated for 5,070 lux astatine 1 meter.

This means a taxable 1 metre from the airy root volition efficaciously comprehend a small much than 5,000 lumens of airy connected them. If they’re farther away, little of the airy from the root volition deed them, and frankincense the taxable volition look dimmer. This is adjuvant erstwhile buying for a airy due to the fact that you mightiness not request the brightest lights successful the world. You lone request to guarantee the taxable is the close region distant from the airy source.

The Inverse Square Law (and Other Math)

Figuring retired the close region for a airy root isn’t precisely intuitive, due to the fact that of 2 large factors: The archetypal is the inverse quadrate law, 1 of those weird quirks of the beingness that we person to woody with. Put precise simply (mathematicians, delight don’t outcry astatine me), each clip you double the region betwixt the taxable and the airy source, you quadruple however overmuch airy is needed to airy them the aforesaid way.

In different words, it means that each clip you determination doubly arsenic acold distant from a airy source, lone one-fourth of the airy from that root volition deed your subject. So, utilizing the Amaran P60X supra arsenic an example, if it’s rated for 5,070 lux astatine 1 meter, past the taxable volition acquisition astir 1,267 lux astatine 2 meters. Some lights volition specify their lux astatine shorter distances, similar 0.5 meters, which makes it important to marque definite you’re comparing equivalent specs erstwhile looking astatine lights from antithetic manufacturers.