What does the autofocus function of the fixed-focus lens adjust?

The above is the basic concept of photography, and here is a brief explanation.

The "focus" of fixed focus refers to the focal length, which is simply "field of vision". The larger the focal length, the narrower the field of view.

The "focus" of focusing refers to the focus, which is simply the clear point of imaging. Focusing is to adjust the distance of the clear point of imaging, so that you can take clear photos of subjects at different distances in the same field of vision.

Auto-focus is a way for a camera or lens to automatically focus on an object. There are many modes, such as single shot, tracking and point focusing, which meet the needs of aiming at the target subject quickly and accurately. Photographers can choose the appropriate mode according to their own needs.

The aperture adjusts the amount of light entering and the depth of field. The larger the aperture (that is, the smaller the aperture value), the greater the amount of light entering and the shallower the depth of field. F 1.8-F22 indicates that the maximum aperture is 1.8 and the minimum aperture is 22. Aperture, shutter speed and sensitivity constitute the exposure combination of photography, which is one of the most important technical contents of photography. This is best understood through reading and practice.

Incidental: the depth of field refers to the front and back levels of the scene, the depth of the scene, the foreground and background scenes quickly run to the "Jiao Wai" (referring to the focus) and become blurred; In portrait photography, the effect of clear background is the lens effect of large aperture (often combined with telephoto lens-focal length); On the contrary, if the scene is deep, the image will be clear far and near, and it will be unobstructed.