Sony A230 has a
10.0MP APS-C (23.5 x 15.7 mm ) sized CCD sensor and features Bionz processor. On the other hand, Sigma DP3 Merrill has a
15.0MP APS-C (24 x 16 mm ) sized CMOS (Foveon X3) sensor and features Dual TRUE II engine processor.
Sigma DP3 Merrill's sensor provides 5MP more than Sony A230's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the A230 and DP3 Merrill sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A230 and Sigma DP3 Merrill Cameras
Sony A230 and Sigma DP3 Merrill have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Sony A230
or the
Sigma DP3 Merrill ,
including hyperfocal distance.
