Both Sony A57 and Sony A55 have APS-C sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the A57 and A55 sensor size comparison.
Sony A57 and Sony A55 have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.
DxOMark Sensor Scores
Both Sony A57 and Sony A55 sensors have been tested by DxoMark. DxoMark 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. Of the two cameras that we are comparing, A57 has scored 75, 2 points higher than A55.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony A57 |
75 |
23.4 bits |
13.0 Evs |
785 ISO |
Sony A55 |
73 |
23.0 bits |
12.4 Evs |
816 ISO |