In the reviews you can see different ratings, from delight to disappointment. I think the reason is not in the spread of characteristics in different instances, but in a different assessment of the results and a look at the photo in general, i. E. in the target audience. For those who "do not bother", beginners, who do not want to spend a lot of money on something that is not even a hobby, if the result suits themselves, it is quite a good lens. I say without irony, I went through it myself. Press the hole to 6-7, and a lot of shots were taken, which are now nice to look at and maybe someone will not understand why buying more expensive optics for a home album. For those who, either as I tasted fixes (for the sake of curiosity), or had the opportunity to try higher-class optics and SAW THE DIFFERENCE (clean picture, sharpness, color gradient, blur, volume, etc.) - this glass will be passed stage. For me, Sigma 17-50 2,8 became such a zoom, except for fixes from Nikon. True, I had to take a carcass with autofocus correction (d7000), after all, aperture optics from Sigma, correction -15 . although Nikon's 35 / 1.8 G and 50 / 1.8 G on d3100 and 5100 hit right on target. In general, I would advise those who are aimed at growth or a serious hobby - do not waste your time on this glass.
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