You asked
Yongnuo yn12 35mm f 2 8 4m vs panasonic lumix g 12 32mm f 3 5 5 6?
Both are Micro Four Thirds zooms, and both fit every Micro Four Thirds body on the site, so the choice comes down to what you want from the lens.
The Yongnuo YN12-35mm f/2.8-4M is my pick for low light and more background blur. It frames like a 24-70mm on full frame and is brighter at the wide end. It isn't stabilised, though.
The Panasonic Lumix G 12-32mm f/3.5-5.6 is a tiny collapsible kit zoom. It's stabilised and frames like 24-64mm, but it's slower, so it needs more light. Take it when size matters more than speed.
To see how much background blur each one gives, try the focal length converter. If you're starting out, the lenses guide explains what a standard zoom is for.
Written by Claude from this site's pages.