ive been shooting with my D750 for ages but I finally upgraded to a D850 recently and man the low light performance is great but I really need a proper speedlight for these indoor gigs I'm picking up lately. I'm based in Seattle so half the venues I'm in are these dark wood bars or dimly lit basements where I really need that reliable bounce light and the pop-up flash just isnt gonna cut it anymore. I was looking online and everyone keeps pointing towards the Nikon SB-5000 because it's native and has that radio control thing which sounds cool but it's so expensive like $600 is way over what I can swing right now especially after buying new glass. Then I see a lot of people swearing by the Godox V1 or the V860III series saying they're just as good for a fraction of the cost but then I read some forum posts saying the TTL can be hit or miss on Nikon bodies compared to the official ones and I really dont want to be fiddling with manual settings while people are dancing and moving around. My budget is more in the $200-$250 range and I need to get this sorted by mid-October before my cousins wedding since I promised to help out with the photos. Is it worth the extra cash for a used Nikon brand flash or are the third party ones actually reliable enough for professional-ish work these days? Which specific model should I actually be looking at for these bodies?
In my experience, if you are worried about TTL accuracy on a D850, a used Nikon SB-700 AF Speedlight is the sweet spot. It handles bounce light perfectly and fits your budget used. Otherwise, the Godox TT685II-N TTL Flash for Nikon is the best value play. Its basically the V860 without the li-ion battery. TL;DR: Used SB-700 for foolproof TTL, or TT685II to save cash. Both work great for wedding receptions.
Honestly, I have to disagree with the idea that third-party TTL is still a gamble. Over the years, I've used everything from the old Nikon SB-800 to the newest gear, and the current Godox lineup is totally reliable for pro-level work. I've been using the Godox V860III-N TTL Li-ion Flash for Nikon on my own D850 for event gigs lately, and it honestly hasn't missed a beat. The TTL is remarkably consistent, even in those tricky, dimly lit rooms you're describing... it just works. Heres why I'd skip the used Nikon route and go with Godox: