Comparison of ISO settings between E-P3 and E-PL1. Click through to flickr to see a larger version.
There's been some discussion as to how different the E-P3 sensor might be to previous Olympus Pens. I did a test of the respective cameras using the new 14-42mm lens. Above is how the jpgs are rendered using identical in-camera settings.
The difference is actually minimal. It seems at higher ISO's the E-P3 has slightly less noise reduction applied. The E-P3 also has a slightly cooler colour balance.
I did a few raw comparisons, using the supplied raw conversion software, Olympus Viewer 2 and again the results were inconclusive. There does seem to be a marginal improvement in the high ISO performance of the E-P3, but again its not huge.
It does seem as though the E-P3 sensor is basically the same as the previous Pens.
I will do another comparison when the Photoshop ACR update is released, but for now it seems we basically have the same sensor with very minor tweaks.