Samsung ST30 has a
10.0MP 1/3-inch (4.8 x 3.6 mm ) sized CCD sensor . On the other hand, Canon SX30 IS has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Digic 4 processor.
Below you can see the ST30 and SX30 IS sensor size comparison.
As seen above, Canon SX30 IS has a 1.6x Larger sensor area than Samsung ST30. 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.