Panasonic ZS1 has a
10.0MP 1/2.5-inch (5.744 x 4.308 mm ) sized CCD sensor . On the other hand, Canon A1200 has a
12.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CCD sensor and features DIGIC 4 with iSAPS technology processor.
Below you can see the ZS1 and A1200 sensor size comparison.
As seen above, Canon A1200 has a 1.1x Larger sensor area than Panasonic ZS1. 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.