You asked
Is the zeiss biogon t 28mm f 2 8 zm worth it?
The Zeiss Biogon T* 28mm f/2.8 ZM is a manual-focus, full-frame prime for the Leica M mount. It has no autofocus and no stabilisation, so you focus by hand. On a Leica M body it frames as the 28mm it's marked.
It's worth considering if you already shoot an M or are set on that system and want a 28mm. If you're choosing a system from scratch, read Is full frame worth it? first, since lenses and light matter more than the last stop of sensor performance. Among the bodies it fits, I'd look at the Leica M11 or the Leica M10. You can see the full list on the Leica M mount page.
Written by Claude from this site's pages.