Both Panasonic S1 and Sony A77 have 24.0 MP resolution sensors but Panasonic S1's sensor is Full frame (35.6 x 23.8 mm ) and Sony A77's sensor is APS-C (23.5 x 15.6 mm ).
Since Panasonic S1's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Sony A77.
Another difference between these two cameras is that Panasonic S1's sensor lacks 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 S1 and A77 sensor size comparison.
As seen above, Panasonic S1 has a 2.3x Larger sensor area than Sony A77. 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.
DxOMark Sensor Scores
Both Panasonic S1 and Sony A77 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, S1 has scored 95, 17 points higher than A77.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Panasonic S1 |
95 |
25.2 bits |
14.5 Evs |
3333 ISO |
Sony A77 |
78 |
24.0 bits |
13.2 Evs |
801 ISO |