What is the depth of field in photography?

Depth of field (DOF) refers to the distance range between the front and back of an object measured by imaging in front of a camera lens or other imagers. Aperture, lens and object distance are important factors affecting depth of field.

After focusing, the range before and after focusing, that is, the clear image presented in the range of front and rear distance, is called depth of field. There is a certain length of space in front of the lens (before and after focal length adjustment). When the subject is located in this space, its imaging on the negative is just between the two diffusion circles before and after focusing.

The length of the space where the subject is located is called the depth of field. In other words, the blur of the image presented by the subject on the negative plane of this space is within the limited range of the allowable circle of dispersion, and the length of this space is the depth of field.

Depth of field effect refers to the range that can still be clearly seen before and after when the focus is on a certain point. It can decide whether to blur the background to highlight the subject or shoot a clear background.

In the photos of flowers, insects, etc., the background is often blurred (called small depth of field). However, when taking commemorative photos, group photos, scenery and other photos, the background is generally as clear as the subject (called large depth of field).

Extended data

Aperture, the distance between the lens and the subject are important factors affecting the depth of field;

1, the larger the aperture (the smaller the aperture value f) and the shallower the depth of field, the smaller the aperture (the larger the aperture value f) and the deeper the depth of field.

2. The longer the focal length of the lens, the shallower the depth of field, and vice versa.

3. The closer the subject is, the shallower the depth of field is, and the farther the subject is, the deeper the depth of field is.

Baidu Encyclopedia-Depth of Field Effect

Baidu Encyclopedia-Depth of Field (Photogrammetry and Remote Sensing Academic Language)