Each new wave of digital cameras hitting the shelves seem to up the megapixel arms race. But excessive resolutions don’t necessarily make better photos – so why isn’t this message being passed on to consumers?

Only a few of years back, a 8Mp resolution on a compact digital camera would be considered state of the art. These days, you’ll find it on a bargain-bucket model.

You can now buy 14Mp compact digital cameras far and wide. But what do you actually get out of such high resolutions? Strictly speaking, not a lot.

The most obvious benefit of high resolution is that it allows the camera to record more detail in each shot. This is advantageous if you’re printing enlargements, or if you do lots of digital cropping and editing.

But if you’re not blowing your shots up to poster sizes, there’s little need for such a high res. For a standard 6×4 inch print, all you need is 2.2Mp of resolution. For a larger 10×8 inch print, 7.2Mp is perfectly sufficient.

Loss of picture quality

There’s a further argument against the need for such high resolutions – our extensive lab testing has confirmed that high megapixel image sensors often deliver poorer shots in challenging low light conditions. You’re often left with unattractive, grainy results.

To understand why, it’s worth considering how digital pixels actually work. A 14Mp image sensor has 14 million pixels crammed onto it – crudely speaking, exposing each of these pixels to light collectively creates the photo.

But the image sensors in compact cameras are tiny, and they don’t have a lot of space to host all these pixels. By crowding too many pixels onto a tiny sensor you end up preventing each individual sensor from working as well as it can – particularly in dim light conditions.

Think of an image sensor like a flower patch. If you plant too many flowers on it, too closely together, they block each other’s exposure to the sun, and none of them grow as healthily as they would do spaced further apart.

It’s no different for image sensors. In strong light, a 14Mp compact camera sensor does just fine. But when you’re shooting in low light, the overcrowded pixels struggle to make anything out, and you end up with grainy images that lack satisfying detail.

Ultimately, image quality is more a question of sensor size than anything else. No matter how many megapixels you cram onto a tiny compact image sensor, it’ll never match the performance of a large DSLR sensor in dim conditions.

Reducing megapixel counts

What’s interesting is that Canon, Nikon and Samsung have all climbed down in the megapixel arms race with their top-of-the-line premium compact models. The Canon Powershot G11, Nikon Coolpix P7000, and Samsung EX1 all boast restrained resolutions of 10Mp, in a bid to get the best possible shots in low light.

The Canon G11 and Nikon P7000 each replaced older models which had higher resolutions of around 14Mp, so it seems that manufacturers are aware that the most demanding photographers aren’t convinced by the merits of high megapixel counts.

But shouldn’t this message be spread to all potential camera buyers? Have you ever felt misled by camera adverts or salespeople, and ended up paying more for a high megapixel count you may not have needed in the first place?