The art of staying focused

Angela Nicholson Photographer and journalist Angela Nicholson is a former technical editor for Amateur Photographer and has been reviewing and writing about photographic kit since 2004. She’s tested everything from compacts to medium-format cameras and has spent a lot of time working out how to get the best from a wide variety of autofocus systems. Visit www.squeezymedia.com.

There are a few creative exceptions, but one of the fundamental aims of most photographers is to get their subject sharp. Thankfully, that’s the aim of a modern camera’s autofocus (AF) system too but although they are sophisticated, they are not 100% foolproof. There isn’t one go-to setting that guarantees every subject is tack-sharp in every situation. As a result, it’s important to understand how your camera’s AF system works, the conditions that challenge it, and the settings or techniques that will help you to get the results you want.

How does my camera’s AF system work?

There are two types of autofocus systems commonly used today: phase detection and contrast detection. Digital SLRs use phase-detection focusing when the viewfinder is