You asked
Is the tamron 28 75mm f 2 8 di iii rxd worth it?
Yes, if you shoot on a Sony E-mount full-frame body and want one fast standard zoom. The Tamron 28-75mm f/2.8 Di III RXD covers everyday framing from wide to short telephoto, and f/2.8 gives you good low-light performance and soft backgrounds for portraits. It isn't stabilised, so lean on the body's stabilisation if you have it. It works on many Sony E bodies, including the Sony a7 III and Sony a7 IV. On an APS-C body like the Sony a6700, it frames more like 42-112mm. If you're unsure whether full frame is worth the extra money, read Sensor sizes first.
Written by Claude from this site's pages.