Noise in shadows is often a case of underexposure, so try different metering patterns, then make sure you only process noise in post processing, not 'in camera'. Also for top quality don't be tempted to boost the sharpening, saturation, contrast etc in camera, do these things in pp as well. In fact turn Off noise filter (leave noise reduction On) and lower all the other settings from the default level for JPEGS. If you shoot in RAW ACR (or similar) should bring everything back to normal low noise shadows and unblown highlights (assuming your RAW software does not use/transpose the camera settings).
These are the general rules for all 4/3rds sensors, don't let the camera take over, just use it to record the most information, then allow pp to do the rest for top quality images. For lower quality images the camera setting are usually fine.
Steve