What does depth of field mean?

The depth of field means: the distance between the clear images presented by the camera before and after the focus is completed.

When many novices ask senior photographers for advice, senior photographers often mention the concept of depth of field. What does depth of field mean? Let's get to know each other.

0 1 There is a certain length of space in front of the lens (before and after the focus). When the subject is located in this space, its imaging on the negative is just between the same diffusion circles. The length of the space where the subject is located is called the depth of field.

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

When the light rays with parallel optical axes enter the convex lens, the ideal lens should be that all the light rays converge at one point and then spread out conically. The point where all the rays converge is called the focal point.

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.