If you're looking at this lens and shooting with a Nikon, you're probably trying to decide between the Nikon 10.5mm and this Tokina 10-17mm. I shot both with a Nikon 10.5mm Fisheye. and this tokina is 10-17mm and i have to say that this tokina is more versatile than nikon because of the zoom range and honestly the sharpness seems about the same between these two lenses. As expected, Nikon is made to a slightly better quality, but the quality of this Tokina is above standard. I wish this lens was a bit faster (e.g. Nikon f/2.8) but overall I am very happy with this lens. The ability to zoom out to 17mm makes this lens a lot more versatile than Nikon's fixed 10.5mm, because if you zoom out to 10mm you've got a great fisheye and zoom in to 17mm you've got a nice wide-angle lens, itself with a little distortion in the corners @ 17mm you can get very usable wide angle photos.
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