Skip to main content

– Nokia introduced the world’s loudest, brightest and smallest smartphones recently. So now we know that you could light a small TV studio with the radiance from the screen of a Nokia 701, and still hear the music from your Nokia 600 speakers standing close to a power saw.  But hang on, surely that can’t be true? And, by the way, what on earth are lux and nits and phons?

The Nokia 701 is the brightest smartphone on the market – with 1000 nits of luminance equalling 3145 lux, but does that mean – as you might be drawn to conclude – that the screen is three times as bright as a TV studio? And the Nokia 600 is the loudest, blasting 106 phons through its loudspeaker, which is as loud as standing next to a lawnmower. Right?

No – they’re not really that bright or loud. Or not in the way you might think, at first.

Measuring brightness (or loudness) is not straightforward. Because they are measures that depend on more than one thing – and there’s a what-human-beings-make-of-it angle, too.

Nits measure light in a quite different way to what you’re used to from choosing the wattage of a light bulb, to start with. Nit comes from the Latin nitere, to shine. Measuring in nits depends on luminosity (how much light the thing sheds), the solid angle it radiates into and the surface area of the source. So, for example, laptop screens are designed to have a constant ‘nittage’ over a wide, solid angle (because it would be odd and irritating if the screen brightness varied from spot to spot or depending upon the angle).

Lux, on the other hand, depend on luminosity and surface area of the source, and you will often come across it if you buy a video camera: they often includes a minimum lighting level in lux. A camera with good low-light capability will have a lower lux rating. The angle doesn’t matter so much because you’ll be pointing it in the right direction, won’t you?

If you’re old-school and like your light in non-metric units, you can also measure in skots, brils or lamberts.

All clear?

That’s luminance, but do you know how loud a sound is in phons?

Phons are a different beast to decibels, which is actually quite an unhelpful measure when it comes to how ‘loud’ something sounds.

You can listen to two different 60 decibel sounds and they will sound different – quieter and louder – because saying that two sounds have the same intensity doesn’t actually mean they have the same loudness. Human hearing also depends upon the frequency of the sound, so to get the phons you need to plot what’s called an equal loudness curve. Complex sounds can be measured by comparison to 1000Hz test tones, and 60 phons means as loud as a 60dB, 1000 Hz tone.

The Nokia 600 is pretty loud in normal surroundings, sure. But next to a power saw or lawnmower, you’ll still need to move away, we’re afraid. But hey – coupled with a Nokia Essence headset and its 99.8 per cent noise-reduction  – well, let’s just say we look forward to hearing your reports…

Next week, we can move on to measuring distances in parsecs, speed in atto-metres and angles in furmans.