Casio EX-10 has a
12.0MP 1/1.7-inch (7.44 x 5.58 mm ) sized CMOS sensor and features Exilim Engine HS 3 processor. On the other hand, Fujifilm S4200 has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor .
Below you can see the EX-10 and S4200 sensor size comparison.
As seen above, Casio EX-10 has a 1.5x Larger sensor area than Fujifilm S4200. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.