Ricoh GXR P10 28-300mm 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. On the other hand, Ricoh GXR Mount A12 has a
12.0MP APS-C (23.6 x 15.7 mm ) sized CMOS sensor .
Below you can see the GXR P10 28-300mm F3.5-5.6 VC and GXR Mount A12 sensor size comparison.
As seen above, Ricoh GXR Mount A12 has a 13.2x Larger sensor area than Ricoh GXR P10 28-300mm. 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.