You don't always want to put your subject slap bang in the middle of your frame when composing a photo. In fact according to the rule of thirds you should consciously avoid doing so. Most pictures generally work best when the subject is off-centre - ideally one-third of the way into the frame from either side.
The trouble is, most compact cameras, pretty well all cameraphones and even a few DSLRs have not been told about the ‘Rule of Thirds' and seem to insist on focusing on whatever is in the centre of the frame. The further from the centre your subject is placed, the more they struggle to work out what the focal point should be. Even sophisticated cameras with multiple focusing points often get it wrong, especially with small or intricate subjects like this one in the picture above.
Fortunately every camera, even the cheapest of compacts and cameraphones, has a two-stage shutter release button which incorporates a focus lock as the first stage. This enables you to pre-focus on your subject before taking the picture, and using it is easy. Here's how it works.
Lock on to your subject
Place your subject in the centre of the frame and press the shutter release halfway down. The camera (or phone) will lock the focus and exposure but not take a picture.
Reposition
Without releasing your finger from the shutter, reposition your subject to where you want them within the frame, then press the shutter the rest of the way to take the picture.