Meanwhile, I've owned two copies of this Sigma lens and did after about 1500-2000 made digital recordings need to realize both objectives by the same defect or malfunction in both cases:
* Both lenses functioned initially properly upon delivery.
* With two lenses the defect described in further after a long vacation and about 1500-2000 made with the lens shooting occurred.
* If you turn the zoom ring until it stops (upper or lower), and change the zoom direction, so "jump" of the push, that it occurred in two lenses an abrupt change in the zoom level on. The mechanical causes of this "jumping" Zoom I can only speculate and leave it accordingly.
* If you press now the auto focus, it can happen that the zoom once again changed dramatically and therefore the selected area.
* Once focused, the zoom setting not changed often.
* Both lenses stepped occurrence described malfunction also wrong focus and wrong exposure for pictures in uncritical exposure situations. In a repetition of the recording was both usually go ok (but all recordings can not be repeated).
As a meaningful pictures with such a lens is not possible, I have logged into both lenses at Amazon for warranty and returned. The purchase price was paid to me by Amazon. I would like to receive this lens, however, now do not buy again because of this repeated error apparently seem to be a single-copy errors.
