depthoffocus

Depth of field refers to the range of distances within a scene that appear acceptably sharp in a photograph or other optical image. It is a critical concept in photography and cinematography, influencing the overall aesthetic and communicative intent of an image. Factors that control depth of field include the aperture of the lens, the focal length of the lens, and the distance between the camera and the subject.

A large depth of field means that a greater portion of the scene, from foreground to background, will be in focus. This is often achieved using a smaller aperture (higher f-number), a wider focal length lens, or by placing the subject further away from the camera. Large depth of field is useful for landscapes or architectural photography where it is desirable to have everything sharp.

Conversely, a shallow depth of field means that only a narrow range of distances will be in focus, with areas closer and further away becoming progressively blurred. This is typically achieved with a wider aperture (lower f-number), a longer focal length lens, or by bringing the subject closer to the camera. Shallow depth of field is frequently used in portraiture to isolate the subject from a distracting background, drawing the viewer's attention to the main point of interest. The blurred areas are known as bokeh. Understanding and manipulating depth of field allows photographers to control the viewer's perception and emphasize specific elements within an image.