A photograph's depth-of-field determines what's in and out of focus. By controlling depth-of-field, the photographer can draw the viewer's attention to the intended subject. In traditional photography, depth-of-field is controlled by the focal length of the lens, the aperture (ƒ-stop), and the camera-to-subject distance.

In the digital darkroom, Photoshop allows post-production control of depth-of-field. Here, the subject is the tympanum (top) of a gravestone. It is selected and the Unsharp Mask filter is applied in order to bring out detail. Next, the background is selected and the Gaussian Blur filter is applied, causing the background to lose focus. Both these filters are applied with low settings, just enough to achieve a subtle effect.