Both Sony A55 and Panasonic G6 have 16.0 MP resolution sensors but Sony A55's sensor is APS-C (23.5 x 15.6 mm ) and Panasonic G6's sensor is Four Thirds (17.3 x 13 mm ).
Since Sony A55'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 Panasonic G6.
Below you can see the A55 and G6 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A55 and Panasonic G6 Cameras
As seen above, Sony A55 has a 1.6x Larger sensor area than Panasonic G6. 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 Sony A55 and Panasonic G6 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, A55 has scored 73, 12 points higher than G6.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A55
73
23.0 bits
12.4 Evs
816 ISO
Panasonic G6
61
21.3 bits
11.5 Evs
639 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 A55
or the
Panasonic G6 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(APS-C versus Four Thirds),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.
