Nikon L31 has a
16.0MP 1/2.3' (6.17 x 4.55 mm ) sized CMOS sensor . On the other hand, FujiFilm S2800HD has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor .
Below you can see the L31 and S2800HD sensor size comparison.
Nikon L31 and FujiFilm S2800HD have the same 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 S2800HD has 15% larger pixel area (2.04µm2 vs 1.76µm2) compared to Nikon L31, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.