Sony S980 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Sony WX80 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features BIONZ processor.
Below you can see the S980 and WX80 sensor size comparison.
Sony S980 and Sony WX80 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 S980 has 32% larger pixel area compared to Sony WX80, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.