Depth of field pair photography

Depth of field means that the deeper the depth of field, the clearer the background of the photo, the shallower the depth of field and the more blurred the background.

Depth of field refers to the range of the front-back distance of an object measured by imaging in front of a camera lens or other imagers. That is, 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.

It is explained in detail that when the lens of a camera is clearly focused on an object, the points on the same plane perpendicular to the lens axis at the position opposite to the lens center can form quite clear images on the film or receiver, and the points in a certain range before and after the lens axis can also form relatively clear image points acceptable to the eyes. The distance between all the scenes before and after this plane is called the depth of field of the camera.

Before and after the focus, the light began to gather and spread, and the image of the point became blurred, forming an enlarged circle called the diffusion circle.

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.

The foreground depth of field is smaller than the back depth of field, that is to say, after precise focusing, the scene in front of the focus can be clearly imaged, while the scene in the distance behind the focus is clear.

Baidu encyclopedia-depth of field