You asked
Is the tamron sp 85mm f 1 8 di vc usd good for portraits?
Yes, it's a strong choice for portraits, and it's exactly the kind of lens the portraits guide has in mind. The portraits page calls the 85mm f/1.8 the classic full-frame portrait lens: flattering perspective, soft backgrounds and a comfortable working distance.
This Tamron, the Tamron SP 85mm f/1.8 Di VC USD, adds image stabilisation and autofocus, which helps when you're shooting handheld. On full frame it frames as a true 85mm. It mounts on Canon EF and Nikon F, and it's a good match for bodies like the Canon EOS 6D Mark II or the Nikon D750.
If you shoot on APS-C, it still works, but it frames more like 128-136mm, so you'll need to stand further back. A 50mm f/1.8 is a cheaper first step for people if you want something wider to start with.
Written by Claude from this site's pages.