Panasonic ZS3 has a
10.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Panasonic FP1 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Venus Engine IV processor.
Below you can see the ZS3 and FP1 sensor size comparison.
Panasonic ZS3 and Panasonic FP1 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.