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