Pentax WG-10 has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Sony W710 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor .
Below you can see the WG-10 and W710 sensor size comparison.
Pentax WG-10 and Sony W710 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. On the other hand, since Pentax WG-10 has 15% larger pixel area compared to Sony W710, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.