Depth of Field

Although your camera has many focus points, it can only focus on a single point at a time. There will be an area that stretches in front of and behind this focus point that will appear sharp. This area is known as the depth of field.
The depth of field can change in size and can be described as either ‘shallow’, where only a narrow area appears sharp or deep, where more of the picture appears sharp.

To set your camera to use a single focus point, see this article.

There are a few situations where you’ll always want to consider depth of field.

Landscapes
When shooting landscapes, you’ll generally want sharpness from the foreground right through to the horizon.
You cannot focus on an object close to the camera and an object far away from the camera at the same time. You can only focus on one or the other. However, you can get both to appear sharp by increasing the depth of field.

To get as much of a landscape scene as possible to appear sharp, use apertures like F16 – F22 and focus on subjects that aren’t close to the lens.

Landscape photographers often use a technique called hyperfocal focusing to increase the depth of field. This involves focusing at a distance approximately one-third of the way into the scene. This further helps to make everything look sharp.

Close-ups

When shooting up close, use an aperture of F3.5 or as low as your lens allows. Stand back, zoom in and get focus on your subject. This will give a nice depth of field that will isolate your main subject from the background.

Portraits
When shooting people, choosing the lowest aperture your lens allows will blur the background and ensure the main subject of your photo is more prominent. Again, stand back a little and zoom in on your subject to maximise the shallow depth of field.

In the photo at the top of this article, I used an aperture of F2.8. This ensured that Cian is in focus but the background is blurred. To increase an already shallow depth of field, stand back and zoom in on your subject.

Feel free to ask a question or comment below.