Here are a few high-ISO shots. I was taking pics of my daughter's high-school soccer game which started at dusk and finished in the dark, with field lighting. Since my 55-300mm PLM lens hasn't arrived yet, I was shooting with my trusty Sigma 28-300 (or something like that) and nervous about autofocus. Therefore used TAv and with 1/1000 while some natural light, and for these 1/750 sec, f6.3, which seemed to be the sweet spot for focus and freezing movement, with the camera adjusting ISO as needed. I was amazed at how well ISO 36000 came out. These aren't going to be printed poster size obviously, but do a fine job for seeing the kids playing. And I love that the noise doesn't look blotchy, it looks like film grain. Pentax really improved it by an order of magnitude, not just another level or so. (Of note, I selected these pics not because the best, but because there isn't a lot of faces in them, as no permissions, though was a public even of course).
I do wish they could work on color tints at high-ISO. Even though the pics had white jerseys and socks on one team, there is a pronounced color tint in the high-ISO pics, that was not present for the earlier junior varsity game at more normal ISOs (200-400).
These pics have only been reduced in size and converted from DNG to JPG during the export from LR, without other editing.