Design

The 18-200mm sits squarely in Nikon's mid-range family of zooms, and the build quality is therefore noticeably superior to the lower-end kit lenses such as the 18-55mm. The lens feels nicely solid; the barrel is made from metal and high grade plastics, and the metal mount is surrounded by a rubber gasket, which should provide some protection against dust and moisture ingress into the camera body (note however that Nikon don't advertise this lens as weatherproof). Sure it's not up to the standards of the top professional-grade lenses, but that would add additional size and weight (not to mention cost), and in my opinion Nikon have struck a near-perfect balance between build quality and portability, which after all is the whole point of a superzoom.

Serious photographers will undoubtedly welcome the inclusion of a proper manual focus ring and distance scale, especially as Nikon's 'A/M' focusing mode allows manual tweaking of focus even when the camera body is set to AF.

On the camera

The lens feels ideally balanced on larger dSLRs such as the D300, but can feel a little front-heavy on the smaller bodies such as the D40/D60 range (although still perfectly usable). Controls are well-placed; the zoom ring is positioned perfectly for operation by the thumb and forefinger, with the slim manual focus ring then operable by the middle finger. The various switches are also placed within easy reach on the side of the lens barrel. Overall, it's a well considered, easy-to-use design.

One note of caution though; on smaller SLR bodies such as the D60, the lens will block the built-in flash at focal lengths wider than 24mm, resulting in a shadow in the lower center of the image.

Autofocus

This lens features Nikon's compact silent-wave motor for autofocus, which performed extremely well; it's almost silent in operation, and we saw no evidence for any systematic focusing errors. We found focusing to be fast and accurate in everyday use on both the D300 and D60 test bodies, however it must be noted that focus speed and accuracy is dependent upon a number of variables, including the camera body used, subject contrast, and light levels.

Zoom creep

Zoom creep is a common user criticism of this model, and refers to a tendency for the lens either to extend under its own weight to the telephoto position when the camera is held pointing downwards, or conversely to collapse back to the wide angle position when pointed upwards. The effect of this ranges from merely annoyance, when the lens spontaneously extends to telephoto simply from being carried over the shoulder, to a downright nuisance, when the camera is pointed at an angle up or down for shooting and the lens won't maintain its focal length (especially problematic when using a tripod).

Our review sample showed zoom creep between the 24mm and 135mm settings, but only with the camera held near-vertically; however it seems reasonable to expect that the problem will worsen as the zoom ring loosens up with age. This is clearly an issue about which potential users need to be aware, but I wouldn't consider it a deal-breaker except under exceptional circumstances.

Lens body elements

The lens uses Nikon's venerable F mount, and communicates with the body electronically via an array of contact pins. Control of the aperture is mechanical, using a metal lever. The lens mounts by aligning the white dot with that on the body and twisting anticlockwise.
The filter thread is 72mm. It does not rotate on autofocusing, which should please filter users, as should the fact that less expensive 'thick' (8mm mount) polarizers can be used without any vignetting.
The HB-35 hood is provided as standard, and fits positively onto the bayonet mount at the front of the lens. It's pretty solidly made, with a matte black finish on the inside to minimize reflections of stray light into the lens.
The 20mm wide, ribbed rubber zoom ring rotates 100 degrees clockwise from wide to telephoto. The zoom action feels a little uneven across the range, with slightly increased stiffness around 70mm, but this is nothing to worry about in normal use.

The front element extends an impressive 65mm on zooming, with only a little lateral play even at 200mm.
The focus ring is 11mm wide, and rotates 100 degrees anticlockwise from infinity to 0.5m. It does not rotate during autofocus, and Nikon's A/F setting allows tweaking of the focus even when the lens is set to AF. The action on our sample felt noticeably rougher than most similar lenses; however manual focus is still nice and precise, in marked contrast to the 18-55mm kit lens.
A distance scale is provided with markings in both feet and meters, but there are no depth-of-field markings or infra-red correction mark. The focus ring travels slightly past the infinity position.

The lens's angle of view widens very noticeably on moving from infinity to close focus, especially at the telephoto position. Such behavior is common with internal-focus lenses, but rarely to this extent.
Three small switches on the side of the lens barrel control the focus and VR systems. The top one switches focusing between Manual/Auto and Manual modes; the middle one turns vibration reduction on and off; and the bottom one changes the VR mode between 'normal' for everyday use, and 'active' for shooting from a moving vehicle.

Reported aperture vs focal length

Here we show the maximum and minimum apertures reported by the camera at the marked focal lengths.

Focal length 18mm 24mm 35mm 50mm 70mm 135mm 200mm
Max aperture
F3.5
F3.8
F4.2
F4.8
F5
F5.6
F5.6
Min aperture
F22
F25
F29
F32
F32
F36
F36