Landscape photography - depth of field

The perceived sharpness of a photographic image is limited by depth of field.

The higher the depth of field, the more of the image appears sharp from front to back. An image with a shallow depth of field has a shallower and more focused depth of sharpness.

Depth of field can be a very effective tool in photography if used correctly.

By using a short depth of field, it can force viewers to focus exclusively on what is crisp. Because our eyes feel uncomfortable with unclear images, we tend to stare at the sharp parts of the image, and our gaze is drawn to that area of the image, rendering the other unsharp sections of the image hazy and unworthy of our attention. Portraiture benefits greatly from the use of a small depth of field. Most things can be forgiven if the eyes aren't pin sharp as long as they are sharp. People and animals tend to glance at the eyes first, so in almost all portraiture photography, the eyes must be crisp.

Landscape photography, on the other hand, is at the other end of the depth of field spectrum,

with the vast majority of landscape photos requiring a very long depth of field. This is because landscapes are normally attempting to recreate an actual scene as we experience it, and viewers are usually attracted into the image by the image's great depth of field.

_{There are two techniques to control the depth of field. Aperture control is the most frequent method. The deeper the depth of field, the narrower the aperture (the larger the number, e.g. F22). The deeper the depth of field, the greater the aperture (the smaller the number, such as F2.8).}

The depth of field of the apertures in between is proportional to the aperture set along the scale. The second way to control depth of field is to use a camera or lens that allows you to tilt the lens forward or backward. This allows the lens's focusing plane to be more inclined to the subject's plane of focus, resulting in a substantially better depth of field without changing the aperture. It's one of the main reasons for employing tilt lenses or bellows cameras. With such a camera or lens, depth of field may be controlled to a large degree at any aperture.

Depth of field is also determined by the focal length of the lens as well as the camera format in which it is used.

A wide angle lens, for example, always has a much greater depth of field than a telephoto lens. A very wide angled lens, such as a 14mm lens, has a depth of field so great that it almost doesn't require focusing, whereas a 600mm telephoto lens has an extremely shallow depth of field, and the depth of field will always be very limited unless focused on long distance subject matter. Macro lenses, on the other hand, are designed to be able to focus very close to objects. When you start moving in and focusing very closely, the depth of field becomes extremely shallow. The closer you get to the subject, the shallower the depth of field becomes, and in extreme close-ups, even the slightest movement causes the image to blur.