Both Olympus FE-47 and Olympus SP-820UZ have 1/2.3-inch sized 14.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the FE-47 and SP-820UZ sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus FE-47 and Olympus SP-820UZ Cameras
Olympus FE-47 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
Olympus FE-47
or the
Olympus SP-820UZ ,
including hyperfocal distance.
