The first thing you notice about this lens is its focal length range, covering just about everything you could need. Even with all of the coverage it provides, at 19.8 ounces it's not that heavy and fully extends to about 6.3 inches. It's comfortable to carry for long periods of time, especially since it will frequently be the only lens you have to carry. A large (0.75 inch) ribbed rubber zoom ring located at the front of the lens sits within easy reach. The zoom feels adequately dampened even though it suffers from lens creep; when the lens faces down, gravity causes the zoom ring to rotate unintentionally. Manual focusing was good for an AF zoom lens, with a distance scale to show how far you are focused to. With the M/A mode you can manually focus at any time. The lens focuses internally (the front lens element does not rotate during focus), which is helpful when using a circular polarizer filter.
Performance and image quality
In our lab tests, the lens displayed considerable barrel distortion (where objects appear to curve toward the outside of the image) at its widest, 18mm; although noticeable, that's par for a lens this wide. Beyond that, distortion is evident as well, with noticeable pincushion (inward) distortion at 70mm and 200mm. It delivered good sharpness at the center of the image at all points in the zoom range, with the wider end of the range being the sharpest. It also maintained good corner sharpness down to 35mm, with corner sharpness suffering at 18mm. It may not be as sharp as a 50mm prime lens, but considering its zoom range, it is very good. While zooming, the lens maintains its maximum aperture of f3.5 from 18mm to 30mm, at 30mm it shifts to f4 and turns to f5.6 at about 135mm.
To find a competing lens you have to look at one from a third-party manufacturer like the cheaper but unstabilized Tamron 18-200mm XR Di f3.5-6.3 or the similarly priced Sigma 18-200mm DC OS f3.5-6.3.
If you like the convenience of a single lens that you can carry on your vacation, and shoot the kids' ball games as well as family portraits, this lens is worth a look. Though expensive, it does cover the range of several smaller-range lenses for about the same price as each individually. Although it may not have the optical performance of a high-end professional lens, for its range and price it is an all-around good performer.