How do digital cameras take photos with small depth of field? How to set it?

There are three main factors that affect the depth of field: the lens, aperture and shutter used in shooting.

If you want to take photos with small depth of field, the longer the focal length of the lens used, the smaller the depth of field. If you use a lens with a focal length of 100MM and a lens with a focal length of 200MM, the depth of field of 200mm will be smaller at the same position and under the same aperture and shutter.

A large aperture has a smaller depth of field than a small aperture. For example, a depth of field of 2.8 aperture is less than 5.6 aperture.

The faster the shutter speed, the smaller the depth of field. For example, the depth of field of 1/500 seconds is smaller than that of1125 seconds.

As for the ideal depth of field you need, you can use the above three indicators to combine multiple shots, and then take official photos after achieving the ideal effect.