Both Olympus E-PL1 and Panasonic GF1 have Four Thirds sized 12.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the E-PL1 and GF1 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-PL1 and Panasonic GF1 Cameras
Olympus E-PL1 and Panasonic GF1 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.
DxOMark Sensor Scores
At Camera Decision, we also look at Dxo Mark sensors when available as we think it is a good indicator of image quality.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Olympus E-PL1
54
21.5 bits
10.1 Evs
487 ISO
Panasonic GF1
54
21.2 bits
10.3 Evs
513 ISO
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-PL1
or the
Panasonic GF1 ,
including hyperfocal distance.
