Summary: The build quality of this lens is very good. The zoom movement is just tight with no sloppiness. The external rubberized finish is very good. The lens has a very useful range. If you need more wide angle than this, you'd be buying the 10-20 Sigma but the 10-20 has no reach and some distortion to deal with. In comparison, I never noticed really any distortion using the 17-70. I feel pretty confident I can use it through the entire zoom range.
Summary: I have had this lens for a few months now and it is rarely off of my Nikon. The two kit lenses I bought with the d5200 generally stay in the bag. The color rendition is fantastic, the focus quick and accurate and the low light capabilities rival a flat 2.8. I cannot say enough times how pleased I am with this lens. It covers the zoom of a wide and middle range so two lenses in one.
A great value and excellent upgrade from the 18-55 kit lens.
16 August 2013
Summary: If you're looking to upgrade from the 18-55 kit lens but don't want to break the bank then this is the right lens for you. It has a wider aperture of f/2.8-4, which means you'll get 50-200% more light to your camera and shallower DoF. 70mm definitely makes a difference over 55mm. Build quality is very solid, with a metal mount and smooth focus and zoom rings. HSM focuses super fast and is so much more quiet than the grindy motor in the kit lens.
Summary: Paired up with a Nikon D7100 this lens has become a keeper for my DX cameras. I have even tested it manually via adapter on the Fuji X PRO-1 and if one knows knows how to handle wide angle lenses well; they will be very pleased even at the 17 mm setting. I am producing 16 (x) 20 in. prints with no difficulty. Nicely built and easy to handle.
Summary: I wish I found this Sigma lens earlier so I could have saved lots of money on other average lenses. It serves me well when I use it with my D7000 taking indoor photos with Nikon speedlight flash. In one night I took over 300 photos at a party and every photo turned out so sharp. For some reasons, it really gives me an extra sense of confidence when I shoot with this lens. Well done Sigma!
Only minor issues on the d7100, but overall sharp! Also used on D90!
Shoyriazu Yamioka "Toshi", Amazon
26 April 2013
Summary: Update 1 (May 7 2013): I ended up returning my D7100 because I didn't really need to upgrade just yet. So now I'm using it on my trusty D90. The lens is still as sharp as ever. Autofocus is still fast. Having OS is a dream indoors. Since my D90 doesn't have spectacular ISO range before noise shows up, it's nice knowing I can go down to 1/40 or 1/30 and the image comes out tack sharp. I also ended up getting another one of these for a friend and his copy is just as sharp.