Tamron SP 45mm f/1.8 Di VC USD review – Shading

Shading is quite visible at the widest couple of settings on this lens, but that is to be expected. It is rather nice, in fact, so long as you aren’t being scientific. There’s a maximum of 1.2EV fall-off of brightness in the corners at f/1.8, 
which diminishes progressively on stopping down. Most of us will consider it gone by f/2.8, although f/4 will suit the more picky.