vittorio fracassi's reviews
9 out of 10 points and recommendedexcellent construction and sealing, well balanced, fits well in bags, sharp at all focals (more from 70 to 200mm), very fast AF and broad shouldered IS, very good general image qualityimpossible to add extenders, no tripod ring in kit, expensive.
like all good zooms it has a wide field of application both on FF and APS-C cameras. My personal experience disagrees with the results of the resolution results in this Review, probably there are differences in various samples as it often occurs in newly introduced lenses. I had a "good copy" 100-400 and sold it for the liability of weather sealing (the "pump" effect collects moisture and dust) and the, for me, uncomfortable zooming solution. I prefer the 70-300L to it in all respects.reviewed March 22nd, 2011 (purchased for $1)