Having the M.ZD 9-18 and the Panasonic 12-35 creates a slight problem: Since there is some overlap in the focal lengths it's hard not to notice that the 12-35 is a lot sharper than the 9-18. I'd like an ultrawide that's on par with the 12-35. AFAIK, these are my options: Olympus ZD 7-14 + A DSLR lens, so it is optically corrected for distortion. This should give better sharpness in the corners. + Seems very sharp + Weather sealed and built like a tank. - Heavy - Some reviews suggests that it performs better on 4/3 than on m/43 - Also, some reviews says corner sharpness isn't that great at all, especially not on M4/3. Panasonic 7-14 + Sharp, but according to most reviews the difference in sharpness between 9-18 and 7-14 is rather small + Smaller than Olympus 7-14 - Blue blobs that need fixing with rear filter - not weather sealed Sigma 10-20/3.5 with speed booster + Cheap + Will give me 7-14/2.8 + Takes filters + I already own a speed booster. - No AF, but who needs that on a UWA lens? - Probably not so sharp in the corners. Nikon 14-24 + Probably the optically best UWA that money can buy. + Weather sealed and built like a tank. - Heavy - I'll need to buy at least a Nikon D600 to use it, so this will be a very expensive option. Any thoughts? I'm especially interested in whether anyone has used the Olympus 7-14 on the E-M1 and how the results were. And yes, there is a m4/3 7-14/2.8 coming, but I'll have to wait at least a year for it and I'm more interested in lenses that are available now.