Both Sony a5100 and Sony A77 II have APS-C sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the a5100 and A77 II sensor size comparison.
Sony a5100 and Sony A77 II 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
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 a5100 and Sony A77 II sensors have been tested by DxO and the results show that A77 II has a better overall score of 82, 2 points higher compared to a5100's score of 80.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony a5100 |
80 |
23.8 bits |
12.7 Evs |
1347 ISO |
Sony A77 II |
82 |
24.4 bits |
13.4 Evs |
1013 ISO |