Compared to...

Studio scene comparison (RAW)

This is our standard studio scene comparison shot taken from exactly the same tripod position. Lighting: daylight simulation, >98% CRI. Crops are 100%. Ambient temperature was approximately 22°C (~72°F).

Olympus E-620 (RAW) vs. Nikon D5000 (RAW)

Olympus E-620 (Capture One)
Nikon D5000 (Adobe Camera Raw)
4.8 MB JPEG (4032 x 3024)
3.4 MB JPEG (4288 x 2848)

The Nikon is clearly capturing more detail than the E-620. The Olympus isn't really showing any more detail than it did in JPEG, while the Nikon is able to resolve at a much finer level. The use of two different RAW converters (albeit with the same sharpening applied), must be considered but it seems highly likely that Olympus is still using the relatively strong anti-aliasing filter we've seen on the recent E-series cameras.