Lumens Explained for Camp Lights

A lumen is the total amount of visible light a lamp puts out, in every direction or in one beam. That's all it is. It says nothing about how far the light reaches or how pleasant it is to sit under.¹

Lumens, lux and candela

Three units show up on packaging. They're easy to mix up.

• Lumens are the total light the lamp gives off.¹
• Lux is how much of that light lands on a surface. One lux is one lumen per square metre.²
• Candela is how strong the brightest spot of the beam is. The flashlight standard finds it by measuring the brightest spot in the beam.³

Spread the same lumens over a bigger area and each patch gets less light. So lighting a larger area to the same brightness needs more lumens.²

That's why a small lantern can look fine on a table and useless across the campsite.

What beam distance means

Beam distance sounds like "how far you can see". It isn't quite. In the US flashlight standard, working distance is where the light falling on a surface drops to 0.25 lux. The standard says this is comparable to a full moon on a clear night.³

The source's own example: a beam intensity of 1000 candelas gives a working distance of the square root of (1000/0.25), or 63 metres.³

With similar lumens, the light with the higher candela rating makes a more concentrated beam.³ If two lights have similar candela ratings, the one with more lumens makes a wider beam and lights a wider area overall.³

Rough lumen ranges

One source gives these ranges for flashlights. They're a guide to the kind of job, not a rule for what you need.³

Even a small LED flashlight on one AA cell can emit 100 lumens.³ So you don't need a big, heavy light to cover most camp chores.

Reading a box sensibly

• Check whether the lumen figure is for the highest setting. Most camp work happens on a lower one.
• Look for a beam distance or candela figure if you want to see far. A lumen figure alone won't tell you.
• Ignore watts. Different bulbs make very different amounts of light per watt, so power input says little about brightness.³

Brighter isn't better for most camp tasks. Too much light at the table is glare, and it spoils your night eyes. The page on red light and night vision covers that.

Run time is the other half of the box, and reading battery run times explains how to read it.