the Panny 45-150 has got some decent reviews but my initial imatest resolution tests showed poor and highly variable resolution above 150mm (eff). On a relatively small sample size, resolution (tripod mounted with IS turned off) was better with the electronic shutter. My hand held field has similarly varying results. I just shot a more controlled hand held test at 200 and 300mm (eff) and 1/100 and 1/200 sec with mechanical and electronic shutter. 1/100 is not fast enough at 300mm (eff), but 1/200 is okay (pretty poor compared to Canon IS). The electronic shutter images are sharper than mechanical.
This is similar (but not nearly as bad) as the problem with the pancake zoom on the GX1 which caused me to return it. I'm not expecting any big prints at 300mm - but I'm very curious about what's going on and what can be expected of Panasonic "OIS" (although since I saw a problem without OIS tripod mounted, maybe it's a light camera/light lens resonance problem). In a previous post I mentioned my disappointment with the in-body stabilization for the 20mm which probably eliminates the Olympus zooms from consideration and means more testing of the higher quality Panny lenses that I need to make the GX7 investment useful.
So far, I'm inclined to use the electronic shutter (which I think is great otherwise) but which may not work on some moving subjects.
