I am taking it slowly with the camera and only now that I have had a little more experience with it, I decided to find out what it can do at higher ISO.
Here is a shot at 1/150 second at f5.3 and 800 ISO. The full frame shot is 4000 x 3000 pixels and the crop is 1000 x 1000, which represents therefore 1/12 of the area of the frame.
There is noise, but it doesn’t seem too bad. Rather more important it seems to me, is that the image is sketchier and less saturated than it would have been had it been shot at lower ISO. It stills seems fine to me though, for what it is.