Both Panasonic ZS25 and Olympus SZ-31MR iHS have 1/2.3-inch sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the ZS25 and SZ-31MR iHS sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic ZS25 and Olympus SZ-31MR iHS Cameras
Panasonic ZS25 and Olympus SZ-31MR iHS 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 ZS25
or the
Olympus SZ-31MR iHS ,
including hyperfocal distance.
