I've noticed some really weird behaviour on my Sony A7S sensor.
Here's a flat taken on my Tak Epsilon 180ED:
Now here it is stretched:
Notice the vertical discontinuity that occurs precisely halfway across the sensor? This happens at all ISOs and occurs with lenses as well as telescopes.
Now here it is with colour saturation:
Notice the wide horizontal banding on the left hand side of the sensor? It's completely different in character to the right hand half. Again this happens at all ISOs and occurs with lenses as well as telescopes.
Here's an example image (the Shark Nebula in Cepheus) where I've stacked the uncalibrated dithered frames with sigma rejection and then applied PixInsight DBE to highlight the background features:
Again the vertical discontinuity and the banding on the left hand side is clear. If I calibrate with flats then the vertical discontinuity is removed but I can never remove the banding. This has become a fundamental limitiation to the amount of stretch I can apply to my images.
So what is going on with this sensor? Is it using different circuitry on each half of the sensor, perhaps?