Casio EX-Z90 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Digic 4 processor. On the other hand, Panasonic SZ8 has a
16.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Venus Engine processor.
Below you can see the EX-Z90 and SZ8 sensor size comparison.
Sensor Size and Resolution Comparison image of Casio EX-Z90 and Panasonic SZ8 Cameras
Casio EX-Z90 and Panasonic SZ8 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.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Casio EX-Z90
or the
Panasonic SZ8 ,
including hyperfocal distance.