You asked
Tamron 28 300mm f 3 5 6 3 di vc pzd vs canon 70 300mm f 4 5 6?
I don't have a page for the Canon 70-300mm f/4-5.6 here, so I can't compare the two on specs or price. What I can tell you is what the Tamron 28-300mm f/3.5-6.3 Di VC PZD does. It's stabilised, has autofocus, and covers 28-300mm on full frame, so it goes from moderate wide to long telephoto without a lens change. It's made for Canon EF and Nikon F, and it fits a long list of bodies on both formats.
If you mostly want reach for distant subjects, the landscape guide explains why a telephoto zoom is worth having. For closer, flattering telephoto work, see the portraits guide.
Written by Claude from this site's pages.