Camera Accessories

The new AF-S DX VR Zoom-Nikkor 18-200mm f3.5-5.6G IF-ED lens is the largest, heaviest and costliest of the three 18-200mm DSLR zooms we've reviewed in issues 25, 26 and 27. Although it can only be used on Nikon DSLR cameras - where it provides an 11.1x zoom ratio and covers a focal length range equivalent to 27-300mm in 35mm format - it has some distinguishing features that justify its relatively high price tag.

Extended zoom lenses have become popular over the past year or so for their convenience and cost-effectiveness. By covering all the focal lengths you're likely to want with just one lens you save in three ways: no lens changing is required (so the camera's sensor receives less exposure to contaminants), it's cheaper to buy one lens than two or three, and the single lens is lighter to carry and takes up less space in your bag.

However, there are some downsides. Long zooms are seldom as fast as shorter zooms or prime lenses, particularly at the tele end of their range. Their greater size and weight can affect camera handling - especially with lightweight DSLR models. Finally, we've found their overall performance is lower, although whether the fall-off in resolution and increase in chromatic aberration would be detectable by many photographers is debatable.

The new Nikkor 18-200mm lens is the only one of the three we've reviewed to include built-in stabilisation, which appears to be gyroscope-based. Such systems counteract motion by moving lens elements, allowing users to take hand-held shots at slower shutter speeds than would otherwise be possible. Nikon's VR II system has two modes: Normal, which counteracts camera shake and includes automatic panning detection; and Active, which is used where movement is more pronounced and frequent.

Nikon claims a shooting advantage of up to four stops over non-stabilised lenses and our testing showed the claims to be feasible. The Active mode worked well when shooting from a moving platform, such as a boat or car, while the Normal mode was handy for action shots in dim lighting, especially with a camera that performs well at high ISO settings, like the D200, which we used in our tests.

Design-wise the Nikkor 18-200mm lens is highly functional, with a semi-enclosed distance scale half-way along the barrel and marked 18, 24, 35, 50, 70, 135 and 200mm focal lengths - although no IR compensation markings. Maximum apertures change from f3.5 at 18mm to f4.2 at 35mm, f4.8 at 50mm, f5.0 at 70mm and f5.6 at 135mm and beyond. A seven-blade rounded aperture diaphragm produces attractive out-of-focus highlights and the supplied 'flower-shaped' lens hood is relatively easy to attach and remove. The 50cm close-focusing limit, which applies throughout the zoom range, is not quite as close as competing lenses but it's sufficient for a modest macro zoom.

The other significant advantages the Nikkor 18-200mm lens has over its competitors were its fast, accurate and almost silent autofocusing and its generally superior performance (which was almost identical to the two shorter zooms that were also used to test the D200). It's also somewhat better built. The penalties you pay for these advantages are substantial: the Nikkor 18-200mm lens is 7mm longer, 18.4mm greater in diameter and 155 grams heavier, plus $700 more expensive than the Sigma 18-200mm lens reviewed in issue 26.

On the D200, the bulk and weight of the 18-200mm Nikkor was less of an issue than it would be with a lighter camera and the lens was well matched to the sensor in terms of colour rendition and contrast. Flare and ghosting were minimal unless the lens was pointed directly into the sun. Rectilinear distortion was negligible, with only slight barrelling at the widest setting.

Overall image sharpness was good, with highest sharpness between f5.6 and f16, and lowest at the widest aperture. Resolution remained fairly high from f8 to f22 across all focal length settings. Interestingly, the difference between maximum and minimum aperture performance was relatively small, giving the Nikkor lens a clear performance advantage over competitors.

Lateral chromatic aberration was detected at a low level across all focal lengths and most aperture settings. Although unlikely to be visible in A4 prints, its effects may become visible in bigger enlargements. [27]

AF-S DX VR Zoom-Nikkor 18-200mm f3.5-5.6G IF-ED lens
Focal length range: 18-200mm
Maximum aperture: f3.5-5.6
Lens construction: 16 elements in 12 groups
Minimum focus: 0.5m
Filter size:  72mm diameter
Compatible cameras: Nikon DSLRs
Dimensions (Diameter x L): 77mm x 96.5mm
Weight: 560g