What is Depth of Field? How aperture, focal length and focus control sharpness

Understanding depth of field

What is Depth of Field Preview? It's an incredibly useful feature found on many DSLRs that allows you to fine tune your depth of field in camera. Here we explain how to make best use of your camera's Depth of Field Preview feature.

What is Depth of Field Preview step 1

Activate Live View

Your DSLR's Depth of Field Preview function can be used for viewfinder or Live View shooting, but the larger, brighter Live View image makes it easier to judge what is sharp and what is soft. Here, a wide f/2.8 aperture has been selected.

What is Depth of Field Preview step 2

Press DOF Preview

The Depth of Field Preview control is usually found on the front of the camera, next to the lens mount. Press and hold this button and then rotate the camera's control dial to cycle through the apertures available on the lens.

What is Depth of Field Preview step 3

Preview and shoot

The image will become very dark when smaller apertures are selected, although the backlit Live View screen makes it easy to see the effect. Once you're happy with the depth of field, release the DOF preview button and take the shot.