Nikon S6100 has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features Expeed C2 processor. On the other hand, Sony QX100 has a
20.0MP 1-inch (13.2 x 8.8 mm ) sized BSI-CMOS sensor .
Below you can see the S6100 and QX100 sensor size comparison.
As seen above, Sony QX100 has a 4.1x Larger sensor area than Nikon S6100. 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.