Both Olympus SZ-31MR iHS and Fujifilm HS35EXR have 16.0 MP resolution sensors but Olympus SZ-31MR iHS's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Fujifilm HS35EXR's sensor is 1/2-inch (6.4 x 4.8 mm ).
Since Fujifilm HS35EXR'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 Olympus SZ-31MR iHS.
Below you can see the SZ-31MR iHS and HS35EXR sensor size comparison.
Olympus SZ-31MR iHS and Fujifilm HS35EXR 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.