There are several ways to focus a digital camera. There are several ways to focus a digital camera.

1, focus manually. Although all digital cameras now have automatic focusing function, manual focusing can still be used. Many people have the misconception that autofocus is more accurate than manual focusing. Actually, it is not. The advantage of automatic focusing is fast, but manual focusing is more accurate. This is most obvious in macro photography and low light photography. Due to the physical principle of camera autofocus (ranging focus, contrast focus, phase focus), it is easy to appear deviation in weak light, while macro photography needs more accurate focus, so the camera itself is difficult to control.

Many people are used to autofocus, but not to manual focusing. They think focusing is slow and difficult. It doesn't matter. Now most digital cameras have live view function, which is very helpful for manual focusing!

2. Single autofocus. This should be the most familiar way to focus. Single autofocus of a camera means that when the shutter is half pressed, the camera starts focusing. Once the camera processor confirms the focus, it will give a focus prompt, and then press the shutter fully to complete the shooting, and the focusing process is over. If you want to change the focal length, you must first release the shutter button, and then press the shutter halfway to start focusing again. When the camera has indicated that the focus is accurate, but before you completely press the shutter, the subject moves, then you will get an out-of-focus blurred photo, so this focusing method is only suitable for shooting relatively static objects.

3. Continuous autofocus (servo focusing). There are two main types of autofocus. In addition to single autofocus, the other is continuous autofocus. Continuous autofocus, also known as servo focusing, means that the camera locks the target or the focus area after focusing by half pressing the shutter. Once the focal length between the target and the camera changes, the camera will automatically follow the focus. When you use continuous servo focusing, you should choose the focus at the beginning, in other words, tell the camera a clear target so that it can be tracked. According to the characteristics of servo focusing, this method is most suitable for shooting moving targets, such as sports and racing cars.

4. Full autofocus. If you choose autofocus, without making any adjustment, press the shutter with your finger and the camera will automatically help you choose the focus. This is the simplest and easiest way, especially when you need to take a snapshot or don't have time to choose the focus actively. However, the autofocus selection of the camera also has disadvantages. For example, you can't choose the focus you want. The autofocus selection of the camera is often the object near the center of the picture, but there are many times when we choose the focus at other positions in the picture (such as the golden section), so you need to manually select the focus.

5. Select the focus manually. Choosing the right focus manually combines the advantages of automatic focus and manual focus, which can help you control the picture to the maximum extent, especially when shooting scenery, still life and portrait photography, and have enough time to prepare. You can see the indication of the focus in the viewfinder, then press the button to select the focus you want, and then press the shutter halfway to start focusing. It takes a little time, but it's easier to help you take the photos you want.

6. Face recognition. At present, the latest cameras are basically equipped with this technology (real-time view is needed), and the face part in the picture is identified by software algorithm, and then the tracking detection is carried out with this as the focus. This method is most suitable for shooting children who are active. As long as this function is turned on, the focus of the camera will always be locked on the children's faces, so don't worry about Xiong Haizi who doesn't cooperate with every photo!

7. Focus first and then compose. Although the camera technology is becoming more and more mature, the more advanced camera will have more autofocus points for you to choose from, but you can't guarantee that there will be autofocus points in the focus position you need every time. In this case, you can try to re-compose after focusing. This method is very convenient, although sometimes your camera position will be slightly shifted due to the need of re-composition, but this degree of deviation will not change the focal plane and cause defocus. This method is very suitable for shooting in low light environment, that is, focusing the target with the central point (generally speaking, the central point has the best focusing effect), and then moving the camera to re-compose.

8. The key is the back key. Usually when we press the shutter half, the camera will focus automatically, and when we press it all, we will take pictures. In fact, we can also separate the two functions of focusing and taking pictures by setting, so that the shutter only keeps the shooting function, and the autofocus function is placed on the AF-ON button on the back of the machine, that is, the shutter will not focus if it is half pressed. This function of AF-ON is suitable for ecological photography, sports photography, news photography and other occasions where the position of the subject will change at any time, and it is often used.

The usage method is to set the focus point as the central single focus point. When shooting, hold down AF-ON, track the subject with the center focus until the focus is accurate and the composition is completed, and then press the shutter.

Another advantage of using AF-ON is that it reduces the trouble of re-composition. Many times, we need some photos of continuous shooting. If we have to focus on the shutter halfway before taking a picture, and then re-compose it over and over again, it will bring us a lot of unnecessary operations. With AF-ON, you can always track the target you want to shoot, just press the shutter at the right time.

9, hyperfocal distance focus. Hyperfocal distance's concept sounds complicated, but it's actually very simple. Refers to the distance from the front boundary of the depth of field (the nearest clear point to the lens) to the lens when the lens focuses at infinity. In other words, the lens focuses on hyperfocal rather than infinity, and the picture from hyperfocal distance to infinity is very clear. Hyperfocal distance is not a fixed value, it varies with the size of aperture, the length of lens focal length and shooting distance. The larger the aperture opening, the greater the hyperfocal distance, which is in direct proportion. The longer the focal length of the lens, the greater the hyperfocal distance; Hyperfocal distance is directly proportional to focal length, while the relationship between hyperfocal distance and depth of field is: hyperfocal distance is large, and depth of field is small, which is inversely proportional.

The fastest way to focus is not to focus, which is well understood by hyperfocal distance's focusing principle. Manually adjust the focal length of the lens to the hyperfocal distance point to ensure that the subject is out of the nearest clear point, and then you can shoot at will. Many street shooters use this technology. PS: If the wide-angle lens adopts this method, the depth of field of the picture will reach the deepest.

10, depth of field synthesis. This is a very popular landscape photography method in North America. For images with obvious layering, we can take photos of different focal planes, and then synthesize them with this technology to make every part of the image clear.