Panasonic ZS3 has a
10.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Ricoh GXR GR Lens A12 28mm has a
12.0MP APS-C (23.6 x 15.7 mm ) sized CMOS sensor and features GR Engine III processor.
Below you can see the ZS3 and GXR GR Lens A12 28mm F2.5 sensor size comparison.
As seen above, Ricoh GXR GR Lens A12 28mm has a 13.4x Larger sensor area than Panasonic ZS3. 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.