Canon Elph 115 IS has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features DIGIC 5 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 Elph 115 IS and ST600 sensor size comparison.
Canon Elph 115 IS 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.