Pentax P80 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Prime processor. On the other hand, Pentax WG-3 GPS has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor .
Below you can see the P80 and WG-3 GPS sensor size comparison.
Pentax P80 and Pentax WG-3 GPS 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 P80 has 32% larger pixel area compared to Pentax WG-3 GPS, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.