3 Choose the right aperture

Master this vital creative control and take charge of the zone of sharply focused content in your photos

Depth of field is the zone of sharpness in an image. A shallow depth of field keeps only a small area around the focus point sharp, while a deep depth of field creates a picture that is sharp all the way through the frame, from front to back. The ‘look’ you go for has a dramatic impact on the resulting shot, and it’s all controlled by the aperture setting you choose. The aperture itself is basically the size of the hole in the lens that lets light through to the sensor, and low numbers (such as f/2.8) use a very large hole, while high numbers (like f/22, for example) use a very small hole. The effects of aperture and depth of field can’t be created in software, because if you’ve taken a shot with just a shallow band of sharp focus, you can’t then make the whole image look sharp in software, as the data isn’t there. To a degree, you can blur sharp areas to emulate a shallow depth of field in post processing, but it’s time-consuming to do, and the results are often unsatisfactory compared to the real thing. For that reason, this is one thing you need to get right in-camera!