Casio EX-Z450 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor . On the other hand, Olympus FE-4030 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features TruePic III processor.
Below you can see the EX-Z450 and FE-4030 sensor size comparison.
Casio EX-Z450 and Olympus FE-4030 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.