What is the panasonic lumix g 42 5mm f 1 7 good for?

Here is what the site says about that.

From Panasonic Lumix G 42.5mm f/1.7: Panasonic Lumix G 42.5mm f/1.7: A prime lens by Panasonic for Micro Four Thirds cameras, 42mm f/1.7. Specs - Maker: Panasonic - Focal length: 42mm (prime) - Maximum aperture: f/1.7 - Made for: Micro Four Thirds sensors - Mounts: Micro Four Thirds - Stabilised: yes - Autofocus: yes What it frames like - On Micro Four Thirds (Micro Four Thirds): like 85mm on full frame; f/1.7 gives about the depth of field of f/3.4 there. ...

From Focal length converter: Aperture and depth of field: The f-number sets exposure, and that doesn't change with sensor size: f/2.8 gives the same brightness on a phone as on medium format. Depth of field does change. At the same framing, multiply the f-number by the crop factor to get the full-frame aperture with the same depth of field: f/1.8 on APS-C gives about the background blur of f/2.7 on full frame, and f/1.8 on Micro Four Thirds about ...

Quoted from this site's pages.