Cross-posted from Pentax thread..
I recently got a K to M4/3 adapter that can control aperture so I can use my DA lenses (10-17 12-24, 17-50, 70-200 even!) on my E-P2. Previously had an adapter that could not control aperture so I could only use FA31 and A50.
The bigger zooms don't make sense, but it's good to be able to use a specialty lens like the fisheye on both systems now.
Here's a shot with the 10-17 on E-P2, I think the lens "feels" more like a wide-angle lens because the fisheye effect is not so pronounced with the edges cropped off by the smaller sensor. Also, the gridlines in the EVF/LCD make it much easier to compose for symmetry with the fisheye lens compared to the OVF.
Grand Central Terminal, NYC