I want to buy a wide angle lens for my Pana G3, either a 12mm SLR Magic or one of the two 'native' m43 wide angle zooms. I am looking for the best optical quality, good sharpness across the frame, good contrast, lowest CA and - if everything else is equal - the lowest rectilinear distortion. I realise that I cannot have it all. The question is, which zoom? I would be happy with either range of focal lengths (7-14mm, 9-18mm). Optical quality is paramount.