Panasonic S2 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Panasonic FX78 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Venus Engine FHD processor.
Below you can see the S2 and FX78 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic S2 and Panasonic FX78 Cameras
Panasonic S2 and Panasonic FX78 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 FX78 has 16% larger pixel area (2.31µm 2 vs 1.98µm 2 ) compared to Panasonic S2, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Panasonic S2
or the
Panasonic FX78 ,
including hyperfocal distance.