One great camera phone produces an image that's full of detail. Another great camera phone produces an image with similar detail but totally different colouring - but which is 'right'? I explain that 'right' is somewhat subjective and that what you see from a digital camera is always heavily influenced by what the manufacturer thinks you'll prefer to see.

"Ultimately, of course, the answer is that there's no absolute 'right', even at a scientific level - colours of 'reflected' light (as in a real world scene) are subjective by definition. You can hook up a spectrometer and then compare its output to a spectrogram from a captured photo of the same scene and (try to) pronounce 'accuracy' this way, but it turns out that digital camera always 'lie' to some extent."

Here, take a look:

One great camera phone produces an image that's full of detail. Another great camera phone produces an image with similar detail but totally different colouring - but which is 'right'? Ultimately, of course, the answer is that there's no absolute 'right', even at a scientific level - colours of 'reflected' light (as in a real world scene) are subjective by definition. You can hook up a spectrometer and then compare its output to a spectrogram from a captured photo of the same scene and (try to) pronounce 'accuracy' this way, but it turns out that digital camera always 'lie' to some extent.

As we get older, our eyes change and (usually) are able to detect less detail (even with added optical aids like spectacles) - which is why I'm always asking my ten year old what 'that sign over there' says. There will also be changes in how we perceive colours. Then there are environmental issues, with the bright sun in sunnier climates causing colours to seem more naturally vibrant, while the typically overcast or partially-obscured skies of other countries (e.g. the UK) causing colours to seem weak for much of the time. And there are cultural factors, too. Talking to an insider in the camera-phone design business, he confided that even with identical hardware, manufacturers altered the software algorithms that process the raw data from the camera so as to emphasise the colours to a greater or lesser degree depending on the market the phone was being sold into. So, for example, those in the Far East apparently prefer far more saturated colours while in the West we prefer things more muted and 'lifelike'.

So, faced with shots from, for example, the Nokia N82 (left) and Samsung INNOV8 (right) a few months ago it was striking that the split on which of the very different photos was preferred was about 50:50. Even though none of the readers of the piece were actually there at the instant when the shot was taken. Surely both photos can't be 'right'? The fact that the grass is a pleasing shade of green means different things to different people, for whom the very concept of 'pleasing' is different.

Or take a test subject - say a pair of red plastic scissors, shot in sunlight. Lets use the same two test phones again. A big, big difference in colouration. Subjectively, it's clear to me (with the real scissors in front of me) that the INNOV8's photo (on the right) puts a false 'orangeness' into the red handles. While the Nokia N82's photo is fairly accurate but isn't as 'exciting', somehow.

to produce photos that will please the phone's owner. He or she will say 'This produces really nice photos' and the manufacturer's job is done.

Since there's usually no scientific measure available of how accurate the colours are in a scene as perceived by a specific human being's retinas, it actually doesn't matter that the colours in a photo are not quite accurate - all that matters is that the photos look as good as (or artifically better than) the (remembered) scene in real life.

So, remember that the camera neveralways lies. But the likes of Nokia, Samsung and Sony Ericsson are at least lying in order to make you and your subjects look good!