Olympus E-M1 High ISO NR
Olympus E-M1 High ISO Noise Reduction
The Olympus E-M1 offers four settings for noise reduction, or "Noise Filter" as the company calls it: "Off", "Low", "Standard" and "High". The user manual doesn't state at which ISO noise reduction kicks in, so we've started with ISO 100 (extended) to find out.
See for yourself how the Olympus E-M1's "Standard", "Low" and "Off" High ISO NR settings compare to RAW without noise reduction under daylight-balanced lighting. (Note that these RAW images also have no sharpening applied, so they are softer than camera JPEGs at low ISOs.) Click on any of the crops below to see the corresponding full-sized image.
As you can see, all E-M1 noise reduction settings apply noise suppression at all ISOs, even the "Off" setting. The "Low" and "Off" setting do apply progressively less luminance noise suppression than the default, but as you can see, chroma noise is still fairly aggressively suppressed at all settings.
It's interesting to see that JPEGs at the low extended ISO 100 setting show much better detail in the red-leaf fabric than at ISO 200, a much bigger difference than the ISO 100 and 200 RAW files show. It seems Olympus is concerned with showing slightly higher chroma noise at ISO 200 versus 100 in its JPEGs.