Canon N Facebook ready has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features Digic 5 processor. On the other hand, Pentax WG-3 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor .
Below you can see the N Facebook ready and WG-3 sensor size comparison.
Canon N Facebook ready and Pentax WG-3 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 Canon N Facebook ready has 77% larger pixel area compared to Pentax WG-3, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.