Sony WX220 has a
18.0MP 1/2.3' (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features Bionz X processor. On the other hand, Samsung ST600 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Below you can see the WX220 and ST600 sensor size comparison.
Sony WX220 and Samsung ST600 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.