Sony T99 has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Bionz 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 T99 and WG-3 GPS sensor size comparison.
Sony T99 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 Sony T99 has 14% 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.