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. On the other hand, Panasonic ZS8 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Venus Engine FHD processor.
Below you can see the EX-ZR800 and ZS8 sensor size comparison.
Casio EX-ZR800 and Panasonic ZS8 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.