At this time of year, many people are thinking of buying a new digital camera or looking to upgrade their old one. Often the impetus to upgrade is fuelled by the launch of a newer, higher spec version of your own, boasting more megapixels.

The question is: are megapixels really that important?

Often, this dilemma is created by a lack of understanding about how cameras work and what pixels actually are. A film camera collects light from the image via the camera’s lens and exposes it onto the film where that image is recorded. With a digital camera, the film is replaced by a sensor chip which is divided into a collection of Picture Elements (or Pixels). The pixel rating of a camera is measured by multiplying the number of pixels across the chip by the number of pixels down the chip - e.g. a sensor that is 3000 pixels wide by 2000 pixels high will be a 6,000,000 pixel camera, alternatively written as 6 megapixels.

The important thing to realise is that the NUMBER of pixels on the sensor just measures the resolution of the image it records. It has no bearing on the image quality whatsoever. That depends on the optics of the camera (i.e. the quality of the lens) and of the ability of those pixels to record the information. Colour, tone and sharpness are all far more important qualities for an image to have. Ironically, packing in too many pixels on to that sensor can, in some cases, actually reduce the overall image quality. This can be especially noticeable at the cheaper end of the compact camera market.

The other marketing trick to be aware of is that the difference between (for example) a 6 megapixel camera and a 7 megapixel camera appears huge to the consumer and retailers will use that to their advantage. After all, that’s a whole extra million pixels! But in reality that’s just an increase from a 3000×2000 pixel image to a 3200×2200 pixel image. In terms of image editing and use that’s virtually insignificant. Doesn’t seem quite so impressive now, does it?

So, if pixel counts are effectively meaningless, what qualities should we be looking for in a new camera? Well, doing your research at a thorough review site such as Digital Photography Review is a great start. It has highly detailed tests and reviews on a huge range of cameras at all budgets. Once you’ve got a reputable shortlist, you can’t beat seeing a camera at the store and holding it in your hands before making a final decision.