Both Casio EX-10 and Samsung HZ30W have 12.0 MP resolution sensors but Casio EX-10's sensor is 1/1.7-inch (7.44 x 5.58 mm ) and Samsung HZ30W's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Casio EX-10's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Samsung HZ30W.
Below you can see the EX-10 and HZ30W sensor size comparison.
As seen above, Casio EX-10 has a 1.5x Larger sensor area than Samsung HZ30W. 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.