What is the relationship between aperture and depth of field?

Large aperture value and small depth of field; Small numerical value and large depth of field.

The value of the aperture is just the opposite to the amount of light entering.

The depth of field is the clear range before and after the scene in the photographic picture; If a photo is clear from the foreground to the background, it is said that it has a great (or deep) depth of field. If only the subject of a photo is clear and the foreground and background are blurred, we say it has a small (or shallow) depth of field.

The aperture is used to control the amount of light entering the photosensitive surface of the fuselage through the lens. It is an extremely important index parameter of lens, usually in lens. Its size determines how much light enters the photosensitive element through the lens.

We use f value, and the aperture f value = lens focal length/lens aperture diameter. The complete series of aperture values is as follows:

F 1.0, f 1.4, f2.0, f2.8, f4.0, f5.6, f8.0, f 1 1, f 16, f22, f32.

Extended data:

Aperture has three main functions: controlling the amount of light entering, controlling the depth of field and controlling the imaging quality.

Large aperture function:

A, control the depth of field (the larger the aperture, the shorter the depth of field; The smaller the aperture, the greater the depth of field)

That is to say, the aperture changes from f/16 to f/1→ f/8 to f/5.6 to f/4? At this time, the depth of field is getting shorter and shorter, and the scenery outside the depth of field is more blurred, while the subject in correct focus is vivid and clear, attracting attention.

Shutter speed

Because a large aperture is used, there can be more light, thus improving the shutter speed and preventing camera shake.

Make the image sharper and clearer. If you are in a dim light source, you want to capture the environment and atmosphere at that time without the help of a tripod, or you can't use a slow shutter, this is where the large aperture comes in. Therefore, the large aperture lens has always been one of the equipment for film friends.

Small aperture function:

A, the picture quality is clearer than that of large aperture Ming Rui.

From f/5.6 → f/8 → f/11→ f/16 → f/22? The larger the depth of field, the more realistic the description of the scene, and the clearer the picture quality than the large aperture. Ming Rui, a small aperture can reduce the aberration of poor connection or uneven light transmission of lens images and obtain high-quality works.

B, avoid focusing error.

Because of the wide range of depth of field and the large area covered by focus, it has the effect of pan-focus, that is, everything in front and background is displayed one by one. In an environment with difficult focus, such as a high-speed moving object or a dim light source, pan-focus can avoid the out-of-focus blur of the theme caused by focusing errors.

Reduce shutter speed

There is also a small aperture to slow down the shutter speed, and a slow shutter can create a sense of flow.

References:

Baidu Encyclopedia-Aperture, Baidu Encyclopedia-Depth of Field Effect