Both Sony A350 and Sony A550 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 A550 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A350 and Sony A550 Cameras
Sony A350 and Sony A550 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 Sony A550 sensors have been tested by DxO and the results show that A550 has a better overall score of 66, 1 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
Sony A550
66
21.9 bits
11.8 Evs
807 ISO
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 A350
or the
Sony A550 ,
including hyperfocal distance.
