I'm a beginner hobbyist who wants to take long exposure shots of lightning, fireworks, the beach, etc., during both daytime and night time. I would also love to take shots like this. So basically everything from 5 second exposures to 5 minute ones.
I know very little about filters or which ones are "must haves". I've read that you need ND filters especially if you're doing long exposures or want to get a "silky water" effect when the sun is out.
At the moment, I have a Nikon Z6 and a tripod, and a 24mm lens (72mm diameter) and a 50mm lens (62mm diameter). I know that step-down rings exist but they can result in vignetting. I'm not sure if there are any cons to using step-up rings but presumably I can't use a lens hood then.
Alternatively, I could just get a dedicated ND filter for my 24mm lens and use the other lenses without filters, particularly because I'd mainly do long exposures of landscapes with the 24mm, but I don't know yet since I'm still new to this. I've been looking at this NiSi ND kit in particular.
I don't really have a budget, but ideally I'd want filters that only negligibly reduce image quality but are still reasonably priced. Where does the point of diminishing returns start to kick in for ND filters?