FujiFilm S2500HD has a 12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Nikon AW100 has a 16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor .
Below you can see the S2500HD and AW100 sensor size comparison.
FujiFilm S2500HD and Nikon AW100 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 FujiFilm S2500HD has 32% larger pixel area compared to Nikon AW100, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.