Even 18 months ago, a camera with a 6 megapixel sensor was an impressive package. In late 2008 it is basic, and many photographers are turning up their noses at cameras that don’t have at least 12 megapixels.

Traditionally (if you can establish a tradition in the brief time digital photography has been around) the 2 questions to ask when comparing cameras were: how much optical zoom and how many pixels ~ in both instances the right answers was “the more the better”.

For optical zoom, the more the better still holds true, although there is a price to pay or wider zoom ranges, in heavier lenses that pass less light than simpler designs, and that lose something in sharpness as you stretch the zoom factor; but on the whole, 12x and 20x zooms do still tend to be convenient… and they are always better than digital zoom.

The benefit of higher pixel counts is not so clear. If you believe the ads, more pixels means better pictures: they are supposed to give greater resolving power which, in turn, means sharper, more saturated and more detailed pictures. they also promise bigger enlargements. But there is a cost to cramming more and more pixels onto a sensor: noise. Noise is that ugly speckling that degrades your photos and breaks up you images, especially the ones taken in low light.

High megapixel sensors generally perform less well than lower MP system, not better. Not  that you could tell on a screen: to see any improvements, you would have to print out the pictures at A3 and larger poster sizes!

In reality, we have now reached the point where the number of pixels is beginning to reduce image quality enough to need noise reducing software onboard the camera to overcome it. But that software works by smearing the details so you don’t notice how badly the image is breaking up; the end result is a degraded image that then has to be sharpened which causes even more damage.

Film never got to the point where they were fine-grained enough to out-resolve top quality lenses. Not even high contrast speciality films like Tech Pan. One of the reasons for the popularity of Fuji Velvia is its resolving power — the best there is in a colour transparency emulsion and enough to compensate for its over-saturated colours.

In the digital age, things are different: five years ago, Canon’s flagship digital SLR, the full frame EOS 1ds actually out-resolved Canon’s best lenses… not their consumer level glass; it was able to capture more detail than their best lenses could provide. The sensor? At the time it was just 8.8 megapixels.