You've composed your picture perfectly, the subject is managing to keep still, and still the image comes out blurry. Image stabilisation refers to methods employed to keep the camera itself stable so the image is free of blur. The simplest method for preventing that happening is simply to stick your camera on a sturdy tripod.

Of course, carrying a tripod isn't always practical, and sometimes even when mounted on a tripod the vibration from pressing the shutter button can jar the camera enough to cause blur. Manufacturers are now adding clever systems to their cameras that will keep the image stable, but are also guilty of giving misleading names to inferior methods.

There are different ways of reducing blur and confusingly manufacturers give them various and often contradictory names. Labels such as 'image stabilisation', 'anti-shake', 'vibration reduction' and various combinations are bandied about and mean different things to different companies. Cutting through this fog of marketing misinformation, make sure you look for a camera that employs a mechanical means of reducing blur.

Mechanical image stabilisation detects the tiny vibrations from your hands and compensates by fractionally moving the image sensor inside the camera. This is becoming more common in compacts, even those as small as the Nikon S500.

Some dSLRs also move the sensor, while some dSLR lenses move elements of the lens to steady the image as light passes into the camera. When shooting with full manual control over your camera, mechanical image stabilisation can potentially save you two or three exposure stops. This would mean that you could, say, employ a slower shutter speed to capture more light without the palpitation of your hands blurring the image.

A method that doesn't involve physical movement is more commonly found in compact cameras. This simply fires the shutter so quickly that vibrations do not have time to jog the picture. To compensate for the fast shutter speed, the camera automatically increases the light sensitivity, or ISO, of the camera, so that the sensor gets more information in less time.

The problem with this is higher ISO levels generally lead to grainy speckles, or noise, in the final image. This method is really just a cheap fudge and in our book shouldn't qualify to be known as any variation of 'image stabilisation', 'anti-shake' or 'vibration reduction'. 

That said, Fujifilm has worked on improving the quality of its sensors so that the non-mechanical method in cameras such as the FinePix F40fd can produce decent-quality images at higher ISO settings. Until other manufacturers follow this example, the altered sensitivity approach is best avoided. Some cameras employ both methods, but that's all the more reason to avoid the non-mechanical high-sensitivity setting and stick with the mechanical approach.

Whatever kind of image stabilisation you go for, the best way to avoid shaky pictures is the time-honoured low-tech method of steadying the camera yourself. Place the camera on a tripod or a wall and use the timer to avoid vibrating the camera as you press the shutter button. Consider bracing your elbows on a wall, fence, or anything fixed. As a last resort, tuck your elbows into your body to minimise the amount the camera can waver around. Happy blur-free snapping!