Both Olympus SH-3 and Olympus SZ-16 iHS have 16.0 MP resolution sensors but Olympus SH-3's sensor is 1/2.3' (6.17 x 4.55 mm ) and Olympus SZ-16 iHS's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Olympus SZ-16 iHS'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 SH-3.
Below you can see the SH-3 and SZ-16 iHS sensor size comparison.
Olympus SH-3 and Olympus SZ-16 iHS 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.