What are the main factors that affect the depth of field?

The main factors affecting the depth of field are as follows:

1. pore size:

Aperture is a parameter of camera lens, which is expressed by f/ number. Smaller aperture (large f/ number, such as f/ 16) can bring greater depth of field and make the foreground and background appear clearly. On the contrary, a larger aperture (small f/ number, such as f/2.8) will lead to a shallower depth of field, which will only make some parts of the scene clear and others blurred.

2. Focal length:

Focal length refers to the focal length of a lens, usually expressed in millimeters (mm). A longer focal length (e.g. 200mm) will bring a shallower depth of field than a shorter focal length (e.g. 24mm). When shooting distant objects, a long focal length lens may lead to blurred background, but when shooting close objects, the choice of focal length will directly affect the depth of field.

3. Shooting distance:

Shooting distance refers to the actual distance between the photographer and the subject. A longer shooting distance usually leads to a larger depth of field, because the distance between far and near objects is smaller. However, shooting at close range will lead to shallow depth of field, because objects at relatively close range may have inconsistent focus and some objects may be blurred.

4. Sensor size:

The sensor size of the camera also affects the depth of field. A camera with a large sensor usually has a shallow depth of field, which makes it easier to blur the background than a camera with a small sensor. This is one of the reasons why full-frame cameras have better background blur effect than ordinary digital cameras.

5. Shooting angle:

The shooting angle refers to the angular relationship between the photographer and the subject. When the camera is parallel to the object, the whole object may remain clear, while when the camera is parallel to a certain part of the object, only that part may remain clear and other parts may be blurred.

6. Preview of depth of field:

Modern cameras are usually equipped with preview function of depth of field. Photographers can preview the depth of field effect under different aperture, focal length and shooting distance through the viewfinder or the depth of field preview button on the screen. This allows the photographer to know the clear area of the photo in advance before shooting, which helps to better control the depth of field.