You asked
Nikon z50 vs sony a6400?
Both are APS-C mirrorless cameras from 2019, and both use a 1.5x crop, so lenses frame the same way on either. Neither has stabilisation in the body, so you'll want stabilised lenses for slow shutter speeds.
I'd lean towards the Sony a6400. It's small and very quick to focus, and it has a much bigger lens range on this site. The Nikon Z50 has 20.9 megapixels to the a6400's 24.2, and it's a fine choice if you already own Nikon Z lenses.
For an everyday kit, try the Nikon Z DX 16-50mm f/2.8 VR on the Z50, or the Sony E 18-55mm f/3.5-5.6 OSS on the a6400. The Sony a6100 is the cheaper body with the a6400's autofocus. If you're still choosing your first camera, the first camera guide explains why mirrorless is the sensible starting point.
Written by Claude from this site's pages.