Olympus' default JPEG compression still results in ringing artifacts -- the halos on edges -- among other slight issues. I didn't push the raw color noise reduction as much as I could have, so you can see a little more in the way of colored speckling than I'd like on the raw sample, but you get the picture.
Shadowed areas show a lot of processing artifacts at ISO 3200, but well-illuminated areas like the text can hold up OK. By ISO 6400 there's generally too much detail degradation. While shots like this look pretty bad at high ISO sensitivities, depending upon display size and scene content you may be able to still use them.
If you're willing to go a little grainier, you can get much sharper detail in the midrange ISO sensitivities, at least compared with the default Fine-quality JPEG.
(1/125 sec, f1.8, spot metering, AWB, ISO 800, 45mm lens)
While this is noisy and full of artifacts on close inspection, it does pretty well at preserving the tonal range and detail, so some folks might find its images usable at this high ISO sensitivity.
(1/60 sec, f3.5, spot metering, AWB, ISO 25600, 12-40mm lens at 40mm)
While gone is gone on really clipped highlights, it does a good job on moderate cases. In low ISO sensitivitiy images you can bring up shadow detail without introducing noise.
(1/100 sec, f4.5, ESP metering, AWB, ISO 200, 12-40mm lens at 40mm)
