Unfollowed the astro-rule about shooting at ISO 100, now my shots have grain I can't fix
My old photography club leader insisted that any ISO above 400 ruins deep sky photos, so I spent 2 years stacking at ISO 320 while my buddy in Tucson shot the same nebula at 1600 and got way better signal, so who's actually right on this, or is it all just camera-dependent?
Its the same thing I keep seeing with workout advice or cooking rules, someone turns a thing that works in one setup into a hard law for everyone. Your club leader probably shot an older camera where high ISO really was a mess, and for that sensor he wasnt wrong. But a newer camera handles 1600 fine, and the whole point is getting enough signal so you can stack away the noise. Tucson skies alone give your buddy a head start too, way less light pollution than most places. So the real answer is its camera and sky dependent, not a magic number, and chasing ISO 100 just made you lose faint detail for two years.