Ricoh GR Digital III has a
10.0MP 1/1.7-inch (7.44 x 5.58 mm ) sized CCD sensor and features GR engine III processor. On the other hand, Casio EX-ZR10 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features Exilim Engine HS processor.
Below you can see the GR Digital III and EX-ZR10 sensor size comparison.
As seen above, Ricoh GR Digital III has a 1.5x Larger sensor area than Casio EX-ZR10. 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.