A Minolta MD 1.4 50mm lens ("normal lens"). The distance scale is on "infinite", "8" is selected as the aperture.
The area that is in focus with these settings is easy to read on the lens.
Just look at the lines below the ft and m scales - see the two yellow arrows! Correct!
The depth of field is around 10m to far beyond infinity - see the two white arrows!
The depth of field increases at f / 16 from 5m to far beyond infinity - you can now easily check that too!
The same Minolta MD lens. The distance scale is now on "3 meters", "8" was selected again as the aperture.
As you can see, the depth of field now ranges from approx. 2.5 meters to approx. 4 meters!
Even with aperture "16", the subject in the picture is only shown in focus from around 2 meters to just under 10 meters.
Tip: There are a number of apps for your smartphone that automatically calculate the depth of field for a variety of focal lengths and distance settings.
Tip: As a rule of thumb, wide-angle lenses offer a greater (larger) depth of field than normal or telephoto lenses at the same distance from the camera to the subject.