Both Panasonic SZ10 and Sony NEX-5T have 16.0 MP resolution sensors but Panasonic SZ10's sensor is 1/2.33' (6.08 x 4.56 mm ) and Sony NEX-5T's sensor is APS-C (23.4 x 15.6 mm ).
Since Sony NEX-5T'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 Panasonic SZ10.
Below you can see the SZ10 and NEX-5T sensor size comparison.
As seen above, Sony NEX-5T has a 13.2x Larger sensor area than Panasonic SZ10. 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.