By clicking one of our links you're supporting our labs and our independence, as we may earn a small share of revenue. Recommendations are separate from any business incentives.
DxO Labs have published detailed Raw-based image quality data and DxOMark Sensor rankings for the Panasonic Lumix G1, Olympus E-420 and E-510. You can check out the finding at http://www.dxomark.com.
"Despite the difference in overall size, however, both conventional Four Thirds cameras and Micro Four Thirds cameras have the same image sensor size and specifications. This means that photographers can easily compare both kinds of cameras' Raw-based performance on the DxOMark Sensor scale, regardless of other differences (optics, ease of handling, etc.)."