DEPTH OF FIELD: This refers to the area in focus from near to far.  It is narrower at large apertures (f.2).  And it is wider (deeper) at small apertures (f.16).

 Also, at high magnification (ZOOM IN), or if you are close to your subject, and use a large aperture (small number), the Depth of Field is reduced (narrow).

Tip: So if you want a narrow Depth of Field, use your zoom &/or get closer to your subject and increase the aperture size to (f.2).

Tip: If you want a large Depth of Field, with sharper images, ZOOM OUT – or get back from the subject and use a small aperture (f. 8 - f.16). (Though, because less light is hitting the sensor, a longer shutter speed will be required).