Olympus XZ-10 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor . On the other hand, Casio EX-ZR800 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features EXILIM Engine HS 3 processor.
Below you can see the XZ-10 and EX-ZR800 sensor size comparison.
Olympus XZ-10 and Casio EX-ZR800 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 Olympus XZ-10 has 35% larger pixel area compared to Casio EX-ZR800, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.