Both FujiFilm S2500HD and Samsung EX2F have 12.0 MP resolution sensors but FujiFilm S2500HD's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Samsung EX2F's sensor is 1/1.7-inch (7.44 x 5.58 mm ).
Since Samsung EX2F'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 FujiFilm S2500HD.
Below you can see the S2500HD and EX2F sensor size comparison.
As seen above, Samsung EX2F has a 1.5x Larger sensor area than FujiFilm S2500HD. 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.