Panasonic ZS3 has a
10.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Leica X1 has a
12.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor .
Below you can see the ZS3 and X1 sensor size comparison.
As seen above, Leica X1 has a 13.5x Larger sensor area than Panasonic ZS3. 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.