Hi,
I have the GX680 III and GX680 IIIS
I have the 65mm, 100mm, 190mm and 250mm lenses.
For portraits, the 190mm is specialized and provide soft focus at one aperture and regular sharpness at all other apertures. The 250mm lens is also a good choice for getting blurred backgrounds and great bokeh.
Please drop me a line if you are interested.
- Tom