How to zoom the focal length to infinity?

1. Make sure that the camera/lens is in "auto focus" (AF);

2. Auto focus on distant scenery or luminous objects (such as distant mountains, the moon, etc.). );

3. When you hear the sound of autofocus, you know that the lens has been focused to infinity;

4. At this time, immediately set the camera or lens to "Manual Focus" (MF) to avoid touching the focus ring (if any) on the lens, so that the lens is always locked at "Infinite Distance";

Extended data:

The principle of stretching the focal length to infinity;

Anyone who has studied optics knows that distant objects will form an inverted and reduced real image at the focal point on the other side of the convex lens.

Camera shooting will form an area called depth of field before and after the imaging focal plane, which is the acceptable range of imaging clarity.

Usually, when the camera is aimed at an object 20 meters away, the depth of field of the photo may start from 15 meters away from the camera and extend to infinity.

When the lens used by the camera is fixed, the depth of field of the photo is related to the aperture size. The smaller the aperture, the wider the depth of field.