I live in the Peruvian Amazon jungle and bought this lens about a year ago thinking it would be just the ticket to capture the vast expansiveness of my surroundings without having to lug about a heavier and sturdier lens with about the same focal length options. Not 8 months later, even though I'd treated the lens with all the respect it deserved, it became contaminated with fungus and could no longer be used. I took it to my German camera maker in Los Angeles when I returned there last month who, after attempting to disassemble same, pronounced it "Kaput" as, because the lens groups are spot-tack-welded, they cannot be separated and cleaned, thus rendering the lens quite useless. Nothing of value could be salvaged from it so I chucked it in the bin. I suggest you buy a metal or carbon fibre lens instead...anything but this plastic job which cannot be repaired when trouble with the lens groups arrives.