The depth of field of the depicted space, abbreviated as the depth of field. The depth of field of a photograph depends on the FR, on the aperture, on the distance to the subject, and on the crop factor of the camera’s matrix.
The more FR, the less the depth of field. The wider the aperture is open, the less depth of field. The smaller the distance to the subject, the smaller the depth of field. All professional photographers know this, for example, https://www.artlook.us/service/elopement-videography/.
On cropped CZKs, the depth of field is greater than on full-frame ones with the same viewing angle. For example, if you take a picture on the CZK with a crop factor of 1.5 on a 50 mm FR and take the same photo on a full frame on a 75 mm FR, then the viewing angle will be the same, and the depth of field on a full-frame CZK is smaller.
There is such a thing as hyperfocal distance – this is the distance to the subject at which the depth of field will be infinite, that is, the entire image will be in sharpness. Hyperfocal distance depends on the FR, on the aperture, and again on the crop factor.
DOF is used for artistic purposes. When photographing portraits, getting a small depth of field, you can make a beautiful blurred background, in photography it is called “bokeh”. And when photographing landscapes, on the contrary, they make sure that the depth of field is infinite, and the entire frame is in sharpness.
To calculate the depth of field and hyperfocal distance, you need to use a special depth of field calculator. There are a lot of them on the Internet, there are also various applications on a smartphone that allow you to calculate the depth of field.