You asked
What is the ttartisan m 100mm f 2 8 bubble bokeh good for?
The TTArtisan M 100mm f/2.8 Bubble Bokeh is a manual-focus prime built for full-frame cameras, and its selling point is the soap-bubble highlights it draws in out-of-focus light. If you shoot night lights, fairy lights, or bokeh-heavy portraits and want that look, this is the lens for it. It has no autofocus and no stabilisation, so it suits slower, deliberate shooting.
It mounts on Leica M bodies. I'd start with the Leica M11 for the newest option, or the Leica M10 if you want a cheaper used body with the same mount. The Leica M (Typ 240) also works well. For more on how a 100mm frames people, see the portraits guide.
Written by Claude from this site's pages.