Sigma DP2s has a
5.0MP APS-C (20.7 x 13.8 mm ) sized CMOS (Foveon X3) sensor and features True II processor. On the other hand, Nikon D5500 has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Expeed 4 processor.
Nikon D5500's sensor provides 19MP more than Sigma DP2s'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.
One other difference between these two cameras that is worth mentioning is that Nikon D5500's sensor doesn't have an anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the DP2s and D5500 sensor size comparison.
Sensor Size and Resolution Comparison image of Sigma DP2s and Nikon D5500 Cameras
As seen above, Nikon D5500 has a 1.3x Larger sensor area than Sigma DP2s. 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.
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
Sigma DP2s
or the
Nikon D5500 ,
including hyperfocal distance.
