Summary: First off, the title of the product page says "for Nikon". I bought this lens for half price on e-bay but new, in the box. I paired it with Nikon 3100. The lens works fine in a room with flash but outside it was a nightmare. At 18mm outside the lens can not focus at all, you have to step down to F/8 in cloudy day otherwise the focus always miss the Spot target. I'm not new in photography, I know how to focus. This lens just can't do it.
Summary: I purchased this zoom to use with a Sigma SD1 digital SLR and the combination is really excellent. Its smooth operating, of good quality, and produces very sharp photos at all aperatures and focal lengths. This is a very good "kit" lens.
Summary: I purchased this lense from Amazon and use this lense as my majpor walk around lense ,it is the perfect lense for that.It is great for wide angle shots and for medium telephoto shots. I love this lense.I have three Nikon cameras and I have two of these lenses on two of thw cameras all of the time.Buy one and you will never be sorry.
Summary: I'm really liking the extra reach at the long end (125mm). I bought this lens to replace my Nikon 18-55mm. I have NOT even put the Nikon lens back on my D7000 since I bought the Sigma 18-125mm. I think the lens only comes with a 1 year warranty, I believe. Why can't they offer a longer warranty like Tamron. I believe they offer a 5 yr. I also love the included lens hood. Very nice touch to include that with the purchase.
Summary: Its not an excellent lens but it is not bad either. Pictures are sharp but autofocus tends to hunt a bit especially when using ambient indoor light. Its lightweight which makes it ideal as a good carry around lens withour straining your neck. Much better than the Pentax kit lens considering the longer focal lenght. Definitely takes better pictures than the Tamron 18-200mm.