FujiFilm S2800HD has a 14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Leica D-LUX 5 has a 10.0MP 1/1.63-inch (8.07 x 5.56 mm ) sized CCD sensor .
Below you can see the S2800HD and D-LUX 5 sensor size comparison.
As seen above, Leica D-LUX 5 has a 1.6x Larger sensor area than FujiFilm S2800HD. 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.