Both Canon G5 X and Canon 70D have 20.0 MP resolution sensors but Canon G5 X's sensor is 1″ (13.2 x 8.8 mm ) and Canon 70D's sensor is APS-C (22.5 x 15 mm ).
Since Canon 70D'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 G5 X.
Below you can see the G5 X and 70D sensor size comparison.
As seen above, Canon 70D has a 2.9x Larger sensor area than Canon G5 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 G5 X and Canon 70D sensors have been tested by DxO and the results show that 70D has a better overall score of 68, 6 points higher compared to G5 X's score of 62.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Canon G5 X |
62 |
21.4 bits |
12.3 Evs |
471 ISO |
Canon 70D |
68 |
22.5 bits |
11.6 Evs |
926 ISO |