The lumen figure is the most overrated number

"How many lumens should the lamp have?" is one of the questions we receive most often — and the answer is not the one most people expect: the lumen figure is an indicator of brightness and therefore secondary.

That is not an evasion. Lumens measure the total luminous flux a lamp emits — not how much of it reaches your workpiece, how evenly it is distributed, or whether it dazzles you. For a magnifying lamp shining onto a small area from 20 to 30 centimetres, every model in our range is bright enough. The difference lies elsewhere.

What actually determines light quality

Evenness

A ring of many small SMD LEDs around the lens produces light from all sides with hardly any shadow. That is exactly what a solder joint or a nail treatment needs: no hard shadows cast by your own hand. A point source with twice the lumen figure would be worse here, not better.

Freedom from glare

The light must fall on the workpiece, not into your eye. That is why the LED ring sits behind the plane of the lens and shines downwards. Anyone who wants to finish eight hours at an inspection station without tired eyes pays more attention to this than to any datasheet value.

Colour rendering

How natural colours look under the light is described by the Ra value — and it decides the outcome in cosmetics, dental technology or colour inspection. A lamp with high luminous flux but mediocre colour rendering is the poorer choice for this work. What lies behind the figure is explained in our article on CRI.

Adjustability

A dimmable lamp you can set to 60 per cent is often more pleasant in daily use than a fixed one that is 20 per cent brighter. We have a separate article on that too.

How watts and lumens have developed

A look at our own product history shows why comparing across model years goes wrong. The same lamp, two generations:

Almost a doubling of luminous flux for 3 watts more consumption — that is the LED progress of recent years in a single line. Anyone comparing an old catalogue figure with a current datasheet is comparing two states of technology.

Orders of magnitude in the current range

For orientation, without deriving a ranking from it:

• Series 721X – 60 SMD LEDs, around 950 lumens
• Series 821X – 60 SMD LEDs, 10 watts, around 820 lumens
• Series 851X – 80 SMD LEDs, 12 watts, around 940 lumens

The differences are in the region of 15 per cent. By comparison: for a person to perceive a difference in brightness clearly, it usually takes considerably more. You will hardly notice this difference at your workplace — lens size and colour temperature, on the other hand, immediately.

More LEDs does not automatically mean brighter

The LED count describes how many individual sources the luminous flux is spread across. 80 LEDs instead of 60 primarily mean more finely distributed light with fewer shadows — brightness follows only indirectly. In the 851X both come together, because the larger lens also has a larger area to illuminate.

The practical recommendation

Do not choose by lumens. Choose by the work: lens size and dioptre strength according to your workpiece, colour rendering according to your demands on colour fidelity, dimmability according to how long you work. Brightness then takes care of itself.

And if you are unsure: describe to us what you work on and for how long at a stretch. That leads to the right lamp faster than any datasheet table.