Panasonic FH1 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Panasonic SZ3 has a
16.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Below you can see the FH1 and SZ3 sensor size comparison.
Panasonic FH1 and Panasonic SZ3 have the same 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 FH1 has 32% larger pixel area compared to Panasonic SZ3, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.