Sorry if I pee on someone's parade here, but I think that a small warning would be in place.
The Tamron 70-300 zoom is not a decent lens, not even half decent. They really should have discontinued it. It is not about its sharpness, the image quality is fine, but there is another issue.
You are almost certain to at one point break the AF mechanism, because of a design flaw, which is pointed out in the manual.
The lens has limitations to its "macro" setting, forcing you to set it to Manual focus to switch between modes, and in normal operation, you thus have to operate the focusing mechanism by hand. It cannot focus close at short focal length, but must be set to above 180 mm.
When focusing, the front of the lens rotates, making it difficult to use with polarisers. Moreover, the manufacturer
demands the lens to be set to manual to attach or to remove the hood. I know of three people who have broken the AF mechanism, small plastic cogs, by completely normal operation of the lens.
So it is important that you follow the directions given in the operation manual, to set the lens to MF whenever switching modes from normal to macro or back, and that you never turn the lens barrel when the lens is in AF mode. If you are careful, it will last longer.