Canon S120 has a
12.0MP 1/1.7-inch (7.44 x 5.58 mm ) sized BSI-CMOS sensor and features Digic 6 processor. On the other hand, Sony HX5 has a
10.0MP 1/2.4-inch (6.104 x 4.578 mm ) sized BSI-CMOS sensor and features Bionz processor.
Below you can see the S120 and HX5 sensor size comparison.
As seen above, Canon S120 has a 1.5x Larger sensor area than Sony HX5. 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.