Summary: I've used this on both DX and FX format cameras. On a DX (Nikon D300) it is very sharp and the images have very nice contrast. On a full-frame FX sensor (I was using the D800), the outer edges of the image are not so crisp as the center portion.
Summary: I bought this lens for a used Nikon D70 that I bought on ebay, and it's been a good lens. I have only had a couple of instances where it threw up an error, but all it took was a removal and reattachment of the lens - and even then that hasn't happened very often.
Summary: If you want to get an ultra zoom, which despite their problems in quality arr useful if you want to carry only one lens, most people's first choice is the Nikon 18-200mm; if you can find one and afford it. The second is Tamron's 18-250mm lens.
Summary: After I bought the D50--my first DSLR--I went on the hunt for a good all-around lens. I was upgrading from a fixed lens system with 10X optical zoom, so I would settle for nothing less than a lens with 10X zoom equivalent.
Summary: Nikon has discontinued this lens, which is a shame. It is lightweight, sharp, and makes a perfect walk around lens for any full frame (FX) Nikon DSLR like the D700. I bought mine used, for more money that it originally sold for new. Ken Rockwell gives this lens very high marks.
Summary: I have owned and used two copies of this lens. The first was remarkably sharp, at all focal lengths, just as other reviews had led me to expect. Unfortunately it was a used copy with a significant undisclosed flaw on the front element, so I returned it.