These are lens cap shots. Lens cap installed during exposure.
100% views of three raw files. The first is a 60 second exposure at ISO 100 with the camera at ambient temp, inside my house, no sun exposure.
Second is another 60 second shot, but this one is at then end of a 60-shot sequence of 60-second exposures. Same conditions as above. So, the end of 1 hour of continuous exposures. The body was warm to the touch, but far from hot.
The third was a 4 second shot taken after the 60-shot sequence.
This first snapshot is from Capture One, 100% view, with the "Single Pixel NR" disabled. I'm zoomed into the lower left corner, where the hot pixels seem to be the worst.
Second is with the exposure pushed 4 stops, again, no single-pixel NR:
Third is with the single-pixel NR enabled (you can see the slider in the left panel, set to 20 out of 100, which is stronger than I normally need to use it) along with the 4-stop push:
So, as expected, pushing shadows on long exposures results in significantly more hot pixels.
However, my non-pushed images show much less noise than your examples, but I'm not sure if you were pushing those files. And of course ambient temps also play a role.
Also, it's clear that my body has no problem with a short exposure (4 seconds) even after extensive use. So while you may not be willing to trust your S1s with even a few second exposures, I am highly confident in mine (and my S5 as well) under those circumstances.
Some notes on Sony:
One of my regular astro shooting companions - who is highly accomplished in that genre - uses Sony & LR. I asked him if he ever gets hot pixels for astro images (keep in mind that we use trackers and often expose for several minutes at a time), and if so what he does about it, and he said yes, that some images have "a lot" of hot pixels. He also confirmed that LR does not have the equivalent of Capture One's single-pixel tool, so he sometimes has to use the clone/repair tools if he really wants to remove the hot pixels. Additionally, he felt that the current AI hot-pixel removal tool was not yet well suited to astro images, but perhaps it would work for your images.
It would be interesting to see how the various brands stack up with regard to hot pixels in long exposures in a hot environment. In general, I am quite content with Panasonic's approach, but if they ever do offer some kind of automated hot-pixel NR, I strongly would like it as an option that can be disabled. I understand the current approach could be frustrating for LR users, at least until the AI model can be trained better.
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http://georgehudetzphotography.smugmug.com/
Capture One LUMIX FF feature request thread:
https://www.dpreview.com/forums/thread/4658107#forum-post-66298057
