<P> DOF is determined by subject magnification at the film / sensor plane and the selected lens aperture or f - number . For a given f - number , increasing the magnification , either by moving closer to the subject or using a lens of greater focal length , decreases the DOF ; decreasing magnification increases DOF . For a given subject magnification , increasing the f - number ( decreasing the aperture diameter ) increases the DOF ; decreasing f - number decreases DOF . </P>
to increase the depth of field what must you do to magnification
decreasing magnification increases DOF