Both Pentax WS80 and Sony HX5 have 10.0 MP resolution sensors but Pentax WS80's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Sony HX5's sensor is 1/2.4-inch (6.104 x 4.578 mm ).
Since Pentax WS80'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 Sony HX5.
Below you can see the WS80 and HX5 sensor size comparison.
Pentax WS80 and Sony HX5 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.