Depth Of Field - Canon Rebel T2i Quick Start Manual

Depth of Field

Fixed focal length lenses used to have
depth of field markings on them for
each aperture. Here is a lens on an
older Canon film camera.
Here the markings are indicating that at
f 4, the depth of field will be between
just before and after 2 meters or
between 6 and 8 ft.
Depth of field refers to the area that is
in focus.