Good, versatile walkabout lens

I purchased this lens as a kit with the d40x body, paying the extra $$$ versus the 18-55mm and 55-200mm kit. This lens seemed to be a good compromise both performance- and cost-wise between the normal 18-55mm and 55-200mm kit lenses and the body-only camera and 18-200mm lens. For user/usage reference, I consider myself on the amateur end of the scale that mainly shoots pictures of the kids and their activities, but have some photography experience going back to 35mm film SLR's. Hindsight is usually 20/20, so here are my observations after using the lens for about one month.

I am a recent digital SLR convert from my old 35mm Nikon F-body and lenses, so my comparison is to the "old stuff" as well as the newer kit lenses. This is my first zoom lens, as my old lenses are all fixed focal length.

When I started shopping, I was rather surprised at the build quality of the newer lenses...not nearly the "rock solid", precision feel of the older lenses. However, the 18-135mm lens seemed to have a much better build quality than the other typical 18-55mm and 55-200mm kit lenses. The tolerances on the 18-135mm lens seem much tighter, zoom actuation smoother, and overall weight is heavier (indicating more solid build, but also more weight to carry around). The 18-135mm lens is also physically larger than the 18-55mm and 55-200mm kit lenses, both in length and lens diameter. The zoom range covers 95% of the shooting situations that I have encountered. There have been a few instances where I wished I could have "reached out" farther, but was able to compensate by cropping when processing the picture files later (a function of camera CCD quality, not the lens).

The wide-angle at 18mm provides great indoor coverage for family gatherings, but seems to have some slight distortion to it. Not bad enough that it detracts from the picture quality, but it does seem to have a very slight "fish-eye" effect, which may be an expected result at that focal length.

At full zoom (135mm), the picture quality is good, but the lens speed drops, so you need to have lots of light or compensate appropriately (i.e. external flash with zoom) in low light conditions.

The auto-focus speed and quality (with my d40x for reference) is consistently VERY good. I have been impressed with the focus accuracy to date. The zoom ratio using the zoom actuating ring on the lens seems about right... not too fast, but not too slow.

If you plan to ever use manual focus (for portraits or other semi-professional work), I find this lens difficult to focus manually. Even tiny movements of the focus ring can move the focus beyond the desired focus subject. I was told by a sales person that this functionality is intended to mimic the professional lenses for fast focus work, but it is so difficult to get a fine focus, I find that hard to believe.

The advantages and disadvantages I have found on the 18-135mm lens are:

Advantages
- only have to carry one lens (on the camera) vs. two or more (**big advantage**)
- zoom range covers the vast majority of shooting situations
- no lens switching means less dust on the CCD
- Lens doesn't rotate when focusing (vs. 18-55mm and 55-200mm AF-S lenses)
- dedicated manual focus ring on the lens (vs. twisting the lens on the 18-55mm and 55-200mm lenses)
- build quality appears to be much better than the standard 18-55mm and 55-200mm kit lenses.

Disadvantages:
- larger-sized lens obstructs AF assist light
- heavier than 18-55mm lens (but probably lighter than carrying two)
- Lens speed (f-stop) is fairly low compared to non-zoom lenses (e.g. f1.8 on my old 52mm fixed lens) requiring more light or compensation
- Using lens at full wide-angle (18mm) causes the lens to throw a shadow from the flash at the bottom of the picture.
- 67mm lens filters are more expensive than standard (smaller) sizes
- no VR (Vibration Reduction) at higher zoom
- build quality doesn't meet the standards of the "old stuff"

Overall I think this is a great lens that is *almost* perfect for my uses. Any zoom lens is a compromise, so taking all factors into consideration (cost, size, performance, convenience), I am very pleased with the lens, and would recommend it as a good "first lens" for the amateur photographer.