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, Casio EX-H20G has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Exilim Engine HS processor.
Below you can see the EX-Z90 and EX-H20G sensor size comparison.
Sensor Size and Resolution Comparison image of Casio EX-Z90 and Casio EX-H20G Cameras
Casio EX-Z90 and Casio EX-H20G 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.
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
Casio EX-H20G ,
including hyperfocal distance.