Depth of Field Preview
Explore an instant way to check how your chosen aperture is affecting your shot
What is the Depth of Field Preview button, and where is it?
You’ll often find it on the front body of a DSLR: when you press it, it closes down the lens to the aperture you’ve selected, giving you an accurate preview of how much sharpness you will have within your image when you take the shot.
Why does the image go dark when you press it?
When you look through an optical viewfinder it is showing you the scene at a wide aperture, so there is a lot of light allowing you to see a bright scene. But if you stop down to a narrow aperture using the Depth of Field Preview button to see the actual sharpness dictated by your aperture choice, there is less light so the viewfinder becomes darker.
Is this the same on all cameras?
It’s the same with any DSLR that has an optical viewfinder. If you are using a camera with an electronic viewfinder or if you are shooting in Live View, the image you see will not darken when you press the DoF Preview button. If you have a mirrorless camera with an EVF, you don’t technically need a DoF Preview button, because what you see through the EVF in terms of depth of field and exposure is what you are going to get in the image.
Is it worth using the Depth of Field Preview button when you shoot
landscapes, where the depth of field is typically wide?
Depth of Field Preview is a brilliant visual guide to sharpness for anyone shooting with a camera that has an optical viewfinder. Using it with Live View now makes it really easy to see the depth of field given by your aperture choice, and gives you the opportunity to either increase or decrease that sharpness by changing the aperture, so it is worth exploring it if you’ve never given it a go.