“ About using plain Nikon adapters for Nikon lenses:
The cheap ones dont have a aperture control,but the (little) more expensive ones do. The ones without are only suitable for Nikon D series lenses, whereas the ones with control can also be used with Nikon G series lenses.
But recently Nikon removed the mechanical coupling in their newest lenses, and have a electronic one instead.Like canon has done long ago. The "E" designation on Nikon lenses cant be controlled on any type of adapter,because smart adapters for Nikon dont exist (yet)
Other downside of speed boosters is thier price if you use multiple mounts, To buy one for each mount is more expensive than buying a Sony A7 and a couple of plain adapters. ”