A shallow depth of field is often the best choice for portraits. It focuses attention on the subject and hides distracting background detail.
Depth of field is one of the most creative controls we photographers have. By choosing what’s sharp and what’s soft, we can draw attention to the important parts of a scene while de-emphasising everything else.
When we focus on a point in a scene, there is an area in front and behind the point that also appears sharp. This is the depth of field – and it can be expanded or contracted. For example, when shooting a person in a forest, depending on your camera and lens settings, you could choose to record detail in the trees in front and behind the person or transform the trees into an attractive blur.