Panasonic ZS1 has a 10.0MP 1/2.5-inch (5.744 x 4.308 mm ) sized CCD sensor . On the other hand, Olympus FE-4030 has a 14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features TruePic III processor.
Below you can see the ZS1 and FE-4030 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic ZS1 and Olympus FE-4030 Cameras
As seen above, Olympus FE-4030 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.