Under the premise that the 14-bit A-D converter has approximately the range needed to quantize every single photon (<25000 full well capacity, 16K possible values) for low-light shooting raising the ISO is not meaningfully different than adjusting the exposure in Lightroom,
(n.b. I'm taking that as the premise, not asking why that's so or how sensor "gain" really works.) (n.b. This camera does use the Sony Exmor sensor as described in jrista's treatment that this is not a duplicate of. )
Then what is the highest "useful" ISO setting, specifically on the alpha 6000. Has anyone here done experiments and analysis yet?
General reference: Clarkvision's pages (dated camera details).
I don't want to re-discuss theory and misinformation on "gain", so it's not a duplicate. I want to know the specific values of interest for this camera model, to which to apply the "native" and "don't set higher than..." principles to optimize my S/N and (all else being equal) leave one setting alone.
My immediate concern is to get the most out of indoor available light, using a f/1.8 prime lens with OSS. (My ability to handhold long exposure exceeds the ability of subjects to stand still)