I was puzzled by the relative lack of variability in image noise at
different ISO settings with the DMC-GX85 camera. Upon closer
inspection, and aggressive knob twisting, I discovered that the image
noise in the GX85 was deliberately placed there. Just as the E-1 had
dithering noise added to the images, the GX85 also does the same.
This added noise does contribute to an apparent increase in sharpness,
as well as an increase in effective dynamic response.
The noise is uniform across the brightness range (present in both
highlights and shadows) and gives the images a more "film like"
rendering than typical. The E-1 had this feature, as well as the
DMC-L1, but the E-3 and 6D did not.
Speaking of the 6D, the GX85 allows for significant shadow boost (like
the E-1) without looking like the hairball a cat just coughed up.
I'm not sure about the ISO settings yet. It looks like the GX85 is
gaming the ISO a little bit to expand the usable dynamic range while
protecting the highlights.
Themed Olympus Photo Exhibition: http://www.tope.nl/