At ISO 100, there’s a big surprise; the 14th bit is AWOL:
At ISO 200, pretty musc the same thing with a bit more noise. The odd dip to the left of the mean of both green channels is curious:
More of same at ISO 400:
At ISO 800, the red channel is clipping:
At ISO 1600, the trends of the series continue. We are now at about five times the Unity Gain ISO. If you have a good imagination, you might be able to see some periodicity with that period:
At ISO 3200, you might be seeing periodicities of ten counts in the first green channel:
At ISO 6400, we’ve lost a bit in the blue channel and the second green channel.
Based on this testing, I’d have to call the RX-1 a 13-bit camera.