Ricoh CX2 has a
9.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features Smooth Imaging Engine IV processor. On the other hand, Ricoh CX3 has a
10.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized BSI-CMOS sensor and features Smooth Imaging Engine IV processor.
Below you can see the CX2 and CX3 sensor size comparison.
Ricoh CX2 and Ricoh CX3 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. On the other hand, since Ricoh CX2 has 11% larger pixel area compared to Ricoh CX3, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.