Panasonic FS25 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor . On the other hand, Olympus SP-820UZ has a
14.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor .
Below you can see the FS25 and SP-820UZ sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic FS25 and Olympus SP-820UZ Cameras
Panasonic FS25 and Olympus SP-820UZ have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
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 FS25
or the
Olympus SP-820UZ ,
including hyperfocal distance.