Both Canon G3 X and Canon 6D have 20.0 MP resolution sensors but Canon G3 X's sensor is 1″ (13.2 x 8.8 mm ) and Canon 6D's sensor is Full frame (36 x 24 mm ).
Since Canon 6D'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 Canon G3 X.
Below you can see the G3 X and 6D sensor size comparison.
As seen above, Canon 6D has a 7.4x Larger sensor area than Canon G3 X. 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. Canon G3 X and Canon 6D sensors have been tested by DxO and the results show that 6D has a better overall score of 82, 19 points higher compared to G3 X's score of 63.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Canon G3 X |
63 |
21.4 bits |
12.3 Evs |
521 ISO |
Canon 6D |
82 |
23.8 bits |
12.1 Evs |
2340 ISO |