Olympus E-PL3 has a
12.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features Truepic VI processor. On the other hand, Olympus E-PL6 has a
16.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features TruePic VI processor.
Below you can see the E-PL3 and E-PL6 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-PL3 and Olympus E-PL6 Cameras
Olympus E-PL3 and Olympus E-PL6 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.
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 E-PL3
or the
Olympus E-PL6 ,
including hyperfocal distance.