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, Sigma DP3 Merrill has a
15.0MP APS-C (24 x 16 mm ) sized CMOS (Foveon X3) sensor and features Dual TRUE II engine processor.
Below you can see the SZ-30MR and DP3 Merrill sensor size comparison.
As seen above, Sigma DP3 Merrill has a 13.7x Larger sensor area than Olympus SZ-30MR. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.