Both Samsung WB850F and Fujifilm F900EXR have 16.0 MP resolution sensors but Samsung WB850F's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Fujifilm F900EXR's sensor is 1/2-inch (6.4 x 4.8 mm ).
Since Fujifilm F900EXR'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 WB850F.
Below you can see the WB850F and F900EXR sensor size comparison.
Samsung WB850F and Fujifilm F900EXR have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.