What exactly does focusing mean?

Simply put, focusing is the process of changing the distance between the lens and the sensor so that the focus of the object at a specific position falls directly on the sensor.

Parallel light will pass through the focusing lens of the lens from infinity, so the generalized panaf means that the focus is at infinity, that is, the sensor is placed at a certain distance from the lens, and the focusing lens of the image lags behind an object near the sensor, resulting in image blur. The English name of Focus is focus. Generally, digital cameras have various focusing modes, namely, auto-focusing, manual focusing and multiple focusing modes.

Auto-focus: Traditional cameras use a method similar to visual ranging to achieve auto-focus. The camera emits infrared rays (or other rays), determines the distance of the subject according to the reflection of the subject, and then adjusts the lens combination according to the measurement result to realize automatic focusing. This kind of autofocus-direct, fast, easy to realize and low cost-sometimes makes mistakes (when there is something between the camera and the subject, such as glass, or when the light is insufficient), and its accuracy is very poor, so it is usually not used in today's high-end cameras.

Because the camera emits light actively, it is called active, because it is only a kind of ranging, and it is also called non-ttl because it can't determine whether the lens is in focus correctly through actual imaging. Compared with active autofocus, this focusing method produces passive autofocus, that is, judging whether coking is correct according to the actual imaging of the lens. Judgment is generally based on contrast detection, and the specific principle is complicated.

This is called TTL autofocus because it is realized by lens imaging. It is precisely because this autofocus mode is based on the realization of high lens imaging accuracy and low error rate, but it has complex technology, slow speed (except advanced autofocus lens and ultrasonic motor) and high cost.

Manual focus: Manual focus, by manually rotating the focus ring, adjust the camera lens to make the shooting clear. This method largely depends on the eyes' recognition of the image on the focused screen, the photographer's proficiency, and even the photographer's vision. Early SLR cameras and side-axis cameras used manual focusing to focus.

Nowadays, quasi-professional digital cameras, professional digital cameras and SLR digital cameras are equipped with manual focusing function to meet different shooting needs. Multifocus: Many digital cameras have multifocus or local focal lengths. When the focus is not in the center of the image, multi-focus or multi-focus is used. In addition to setting the focus position, you can also set the focus range so that users can take different images. The most common multi-focus is 5, 7 and 9.

Holographic af Holographic autofocus hologram (af) is a unique function of Sony digital camera and a new autofocus optical system. It adopts advanced laser holographic technology and laser point detection edge theme, and can accurately shoot even in dark environment, with an effective shooting distance of 4.5 meters.

Extended data focusing refers to adjusting the focal length when using the camera, which is called focus in English. Generally, digital cameras have various focusing modes, namely, auto focus, manual focus and multiple focus modes.

Focusing is also called aiming light, focusing. The process of changing the distance and the position of the distance through the camera focusing mechanism to make the image of the object clear is focusing.

Chinese name

concentrate

Foreign name

focus

spell

Duigio

definition

Refers to adjusting the focal length when using a camera.

Mobile phone focusing mode

Contrast focusing, phase focusing and laser focusing.

Reference link: Focus-Baidu Encyclopedia