Both Sony A350 and Nikon D3100 have APS-C sized 14.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the A350 and D3100 sensor size comparison.
Sony A350 and Nikon D3100 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.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Sony A350 and Nikon D3100 sensors have been tested by DxO and the results show that D3100 has a better overall score of 67, 2 points higher compared to A350's score of 65.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony A350 |
65 |
22.6 bits |
11.5 Evs |
595 ISO |
Nikon D3100 |
67 |
22.5 bits |
11.3 Evs |
919 ISO |