So THAT is that mysterious click-clack of the shutter that randomly appears on my A7S2. I've been putting off sending it in for repair, but now I can completely avoid that. Many thanks!
Do you happen to have a link to some documentation for it?
I personally used this trick twice to fix dead pixels on my camera, so I can attest to that.
For cameras without a mechanical shutter, there is instead an option to do it in the menu, for example : (https://helpguide.sony.net/ilc/2010/v1/en/contents/TP0003229...)
Maybe because the FX30 lacks the physical shutter, and instead relies on you putting a lens cao on? If so, I'd expect the A9iii to have the message too.
I think if you can see hot pixels when looking at the raw before demosaicing then the dark frame is not applied (which makes sense, since a DNG is supposed to be more or less a sensor snapshot).
If you do not see them after you processed the raw, I think that would just be your software filtering outliers as best it can, since it would have no way of knowing about the dark frame. I doubt it embeds the dark frame in every DNG, would take up extra space and I am not sure the format even supports that, so likely it just keeps the latest dark frame in memory and applies as part of internal pipeline.