Both Sony RX100 IV and Panasonic GX8 have 20.0 MP resolution sensors but Sony RX100 IV's sensor is 1″ (13.2 x 8.8 mm ) and Panasonic GX8's sensor is Four Thirds (17.3 x 13 mm ).
Since Panasonic GX8'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 RX100 IV.
Below you can see the RX100 IV and GX8 sensor size comparison.
As seen above, Panasonic GX8 has a 1.9x Larger sensor area than Sony RX100 IV. 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
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 RX100 IV and Panasonic GX8 sensors have been tested by DxO and the results show that GX8 has a better overall score of 75, 5 points higher compared to RX100 IV's score of 70.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony RX100 IV |
70 |
22.9 bits |
12.6 Evs |
562 ISO |
Panasonic GX8 |
75 |
23.5 bits |
12.6 Evs |
806 ISO |