At the far end of disappointing otherwise excellent

First, however, once the points that I liked:
+ Excellent sharpness at maximum aperture at all focal lengths in the center which is only slightly better by stopping down.
+ Pleasing bokeh. For a zoom lens in this price range very noteworthy.
+ Excellent workmanship, especially when one is accustomed kit lenses Nikon. Even manual focus in Live View is no problem thanks to the well-damped focus ring. Remarkable for a push in this price range.
+ Faster and more accurate AF. It was not a correction of the focal point necessary.
+ Basic macro function with 2x he (?) Magnification and 22 cm minimum focus distance.
+ No, or very low CAs

Negative evaluate:
- At the far end of the definition is (20% each left and right) even stopped down to f / 8 disaster. This is clearly visible in the 100% view but unfortunately also in the normal view on a 13 "monitor. At longer focal lengths the uncertainty decreases, but it is still present to 35 mm. My experiences meet here with reports in the 17- 70 user group on Flickr. If instead of the center focus an external field is used, then the edge is sharp and the center suffers Here's my good old 18-55 ED II (without VR) significantly better.
- In the 100% image view is not possible, a continuously variable scrolling framing. As a workaround, you can switch to Live View mode and then change to the screen view. Then it goes. This bug seems to occur only on the D7100 and is not very disturbing. He would have been alone for no reason's resending.

This lens has been mercilessly optimized for full aperture performance, which is Sigma succeeded - but unfortunately at the expense of margins. Who is the image center and longer focal lengths concentrated (Portraits, flowers macros) and little landscape and architecture photographed in wide angle, can be accessed safely. Because I wanted to use this lens but as a travel zoom and just wanted to use (compared to my 18-55) at the far end of the mm less it is unfortunately unusable because the edge blur. A great pity, because in all other respects can convince this clear lens

Therefore, I will probably start a trial with the Nikkor 16-85, even though it very rankles me having to lie down 500 for a light-dark weak zoom. And although some now screaming his hands together in horror: my old 18-55 ED II (without VR) is the Sigma at the same aperture visually equal and much sharper, especially in the peripheral areas. Plus, unlike the Sigma, a flyweight ...

Edited on 22 February 2014 (typo)