Fujifilm F900EXR has a
16.0MP 1/2-inch (6.4 x 4.8 mm ) sized EXRCMOS sensor and features EXR II 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 F900EXR and EX-H20G sensor size comparison.
Fujifilm F900EXR and Casio EX-H20G 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.