[staindk]

Thanks for the term! That's a rabbit hole we'll venture down next time I see my dad.

I initially had a paragraph half written out in the comment you replied to detailing how my dad's new cameras perform extremely well at absurd (12800???) ISOs, which "iso invariance" would definitely explain.

My camera is an older Canon 5D MK1 which shoots mostly fine at 200 ISO and lower, and gets grainy quite fast at 400 ISO and above. If and when the photography bug bites me harder I'll probably upgrade to a slightly newer body aha.

[sanitycheck]

Bear in mind you need to shoot raw, not jpg, in order to benefit from this.

In a tricky exposure situation, dial exposure compensation way down (-3 to -5 EV) and take the shot. You probably want a low-ish ISO selected too. Then in lightroom/whatever just crank the exposure slider up and fiddle with the levels & curves - easy way to not blow out your highlights.

[staindk]

Yep good point. RAW is amazing in that regard.