How do SLR cameras get several focus points? This kind of focusing is not focusing on a certain point at a certain distance. But many.

The focusing modes in SLR cameras are auto-focusing, manual focusing and multifocal (the premise is to see what brand of machine you have, but you can generally set it).

1, autofocus:

Automatic focusing is realized by using a method similar to sight distance measurement. The camera emits an infrared ray (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 automatic focusing method-direct, fast, easy to realize and low cost-sometimes makes mistakes (when there is something else between the camera and the subject, such as glass, or the light is insufficient, automatic focusing cannot be realized), and the accuracy is poor. Today's high-end cameras generally don't use this method.

2. Manual focusing:

Manual focusing is a way to adjust the camera lens by manually turning the focusing ring to make the photos clear, which largely depends on the human eye's judgment of the image on the focusing screen, the photographer's proficiency and even the photographer's vision.

3. Multiple focusing:

When the focus center is not set in the center of the picture, multi-point focus or multiple focus can be used. In addition to setting the focus position, you can also set the focus range, allowing users to take photos with different effects. Common multi-point focusing includes 5: 00, 7: 00 and 9: 00.

The place where the focus is right is the clearest. The number of focus points refers to the number of focus points you can find in the viewfinder. Generally speaking, of course, the more the better. The more the number, the more focal points to choose, and the easier the composition. But this is not absolute, because the camera performance is also one of the factors that affect the imaging effect.