Panasonic ZS3 has a 10.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Samsung HZ50W has a 14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Below you can see the ZS3 and HZ50W sensor size comparison.
Panasonic ZS3 and Samsung HZ50W have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Panasonic ZS3 has 40% larger pixel area compared to Samsung HZ50W, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.