Samsung SL720 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Samsung PL120 has a
14.0MP 1/2.3-inch (6.16 x 4.62 mm ) sized CCD sensor .
Below you can see the SL720 and PL120 sensor size comparison.
Samsung SL720 and Samsung PL120 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.