Up through ISO 6400 is usable depending upon what you're shooting. While the two expanded settings can be acceptable under the right conditions, the camera doesn't support raw in the expanded ranges.
This is a particularly egregious example of what happens when a high-frequency pattern interacts with a fast frame rate (60fps) on the X-Trans CMOS II sensor. It's harder to tell, but everything in the focal plane looks noticeably low-resolution during playback. Everything off the focal plane looks nice and well-resolved, though.
