What are the three elements of depth of field?

The three elements of depth of field are the factors that determine the depth of field, mainly including the three factors mentioned in the above table. In the actual shooting process, the shooting conditions vary widely, and it is hard to say which factor can play a decisive role. The three elements of depth of field include:

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.

When shooting, the process of adjusting the camera lens to make the scene at a certain distance from the camera clearly image is called focusing, and the point where the scene is located is called focus. Because "clarity" is not an absolute concept, the scene can be imaged clearly in front of the focus (close to the camera) and at a certain distance behind it. The sum of the front and back ranges is called the depth of field, which means that the scenery in this range can be clear. The depth of field is first related to the focal length of the lens. The lens with long focal length has small depth of field, while the lens with short focal length has large depth of field. Secondly, the depth of field is related to the aperture. The smaller the aperture (the larger the numerical value, for example, the aperture of f 16 is smaller than f 1 1), the greater the depth of field. The larger the aperture (the smaller the value, for example, the aperture of f2.8 is larger than that of f5.6), the smaller the depth of field. Secondly, the depth of field in the foreground is smaller than that in the back, that is to say, after precise focusing, the scene in front of the focus can be clearly imaged, while the scene in the back of the focus is clear.

The spatial depth that can be seen clearly at the same time is called the imaging spatial depth of the eye, that is, the depth of field.

Extended data:

Influencing factors of depth of field:

1, lens focal length

2. The distance of the subject

3, the size of the aperture

4. The size of the photosensitive element (related to the radius of the allowable dispersion circle)

Relationship:

1, the larger the aperture, the smaller the depth of field, and the smaller the aperture, the greater the depth of field.

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

3. The closer the subject is, the smaller the depth of field is, and the farther the subject is, the greater the depth of field is.

In reality, images taken for viewing are observed in some way (such as projection, enlargement into photos, etc.). ). The image perceived by human eyes is closely related to magnification, projection distance and viewing distance. If the diameter of the diffusion circle is less than the resolution of human eyes, the blur produced by the actual image can not be recognized in a certain range. This unrecognizable dispersion circle is called allowable dispersion circle. There is an allowable dispersion circle before and after the focus.

References:

Baidu encyclopedia-depth of field (academic language of photogrammetry and remote sensing. )