Olympus SZ-30MR has a 16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features TruePic III+ processor. On the other hand, Pentax RS1500 has a 14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor .
Below you can see the SZ-30MR and RS1500 sensor size comparison.
Olympus SZ-30MR and Pentax RS1500 have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Pentax RS1500 has 15% larger pixel area (2.04µm2 vs 1.76µm2) compared to Olympus SZ-30MR, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.