(Small) less: a little heavy; Picnic slightly less than a dedicated fixed focus; zoom and focus rings reversed Point; sunshade very good but huge (first visor "made in japan" under my hands); distortion and vignetting marked 17mm but not prohibitive for me, and is easily corrected under "Lightroom" or "DxO"; the small bag delivered is of good quality but not rigid enough for me; Canon Protection Filter necessary to ensure total tropicalization the goal, but twice as expensive as a "Hoya PRO 1D" filter, I do not know which one to take, if you have any advice ...
The (big) plus: zoom tropicalized if fitted with filters; very good resistance to flare; I love his "interchangeable" side, mounted on a full format, it is an ultra wide angle that allows you unprecedented framing landscape, and a small sensor (27- 67) is a little going from transtandard small wide angle to telephoto, useful for the short story; Lens Construction is almost perfect, as each "L", the rings are smooth and precise, the barrel is solid and strong, short responsiveness and reliability are waiting for you if you have heavy use; Zoom itchy rather well (the optimum is between f8 and f11, visibly) and colors typical of an objective "L" saturated and contrasting (though I find it slightly pricks on 7D on 6D to confirm with the progressive mastery of the lens); development "flash" and precise about as fast as the Canon telephoto 70,200 f4 L.
In short, for the price (and the "cashback" current Canon) Affordable reports by other series L, you have a great zoom good dive and versatile. Nevertheless, if you're more into your landscape photographic style, "pixel-peeper" and seek perfection in every corner of the image, better a fixed focal length, or even better a medium or large format camera (although the Nikon D800 and a fixed focal length). I recommend.
12/12/2013 NB: The supplied lens hood is solid but its outer coating is apparently fragile and marks easily. I do not know if it's me or not, after three photos outputs already recorded two light scratches, while the optical "sleeps" in his camera bag, and meticulous use. This is the first time this has happened in such a short time on a sun visor, "L" at that. The "gaffer" I think will be necessary to maintain to nine the sun visor. However, despite this lack of "maniac", I keep the four-star rating because the images produced are really bright, rain or shine, outdoors and indoors (although I prefer a fixed focal length for indoor work / or reduced space, for reasons of size / handling / discretion).
