You asked
Best budget lens for the nikon z8?
For a Nikon Z8 on a budget, I'd look at the third-party primes listed on its Nikon Z8 page. My pick for everyday walking-around shooting is the Viltrox AF 35mm f/1.8 EVO. For people and low light, the 7Artisans AF 50mm f/1.8 is a sensible choice. If you want a little more reach for portraits, the Meike 85mm f/1.8 STM is another affordable option.
A budget lens is still worth buying well. My rule is to split your spending so the lens gets nearly as much money as the body. A modest setup with a good lens will beat a flagship body with a cheap zoom.
Written by Claude from this site's pages.