Both Panasonic GX8 and Sony A58 have 20.0 MP resolution sensors but Panasonic GX8's sensor is Four Thirds (17.3 x 13 mm ) and Sony A58's sensor is APS-C (23.2 x 15.4 m ).
Since Sony A58'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 GX8.
Below you can see the GX8 and A58 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic GX8 and Sony A58 Cameras
As seen above, Sony A58 has a 1.5x Larger sensor area than Panasonic GX8. 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 GX8 and Sony A58 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, GX8 has scored 75, 1 points higher than A58.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Panasonic GX8
75
23.5 bits
12.6 Evs
806 ISO
Sony A58
74
23.3 bits
12.5 Evs
753 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
Panasonic GX8
or the
Sony A58 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Four Thirds versus APS-C),
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.
