Both Nikon S32 and Nikon S33 have 13.0 MP resolution sensors but Nikon S32's sensor is 1/3-inch (4.8 x 3.6 mm ) and Nikon S33's sensor is 1/3.1' (4.7 x 3.5 mm ).
Since Nikon S32'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 Nikon S33.
Below you can see the S32 and S33 sensor size comparison.
Nikon S32 and Nikon S33 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.