Canon S120 has a 12.0MP 1/1.7" (7.44 x 5.58 mm ) sized BSI-CMOS sensor and features Digic 6 processor. On the other hand, Fujifilm F800EXR has a 16.0MP 1/2" (6.4 x 4.8 mm ) sized EXRCMOS sensor and features EXR processor.
Below you can see the S120 and F800EXR sensor size comparison.
As seen above, Canon S120 has a 1.4x Larger sensor area than Fujifilm F800EXR. 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 Canon S120 and Fujifilm F800EXR 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, S120 has scored 56, 15 points higher than F800EXR.