The Nikon 18-105mm ƒ/3.5-5.6 is Nikon's latest ''kit'' lens, sold with the D90 digital SLR camera. The lens is designed to fit a camera with an APS-C (''subframe'') sensor, so while it will mount on Nikon film or FX digital bodies, it will show obvious vignetting when set to any focal length. Small and light, the 18-105mm represents a field of view of approximately 27-158mm in 35mm terms. To economize and create a more efficient design, the lens is equipped with a variable aperture; as the zoom extends the focal length, both the smallest and the largest apertures change. The lens is equipped with Nikon's vibration reduction (VR) technology, advertising a hand-holding improvement of up to three stops.
Sharpness The 18-105mm ƒ/3.5-5.6 provides very sharp results, at least as good as its recent contemporaries and better than previous designs in the same focal length range. Perhaps the best word to describe the sharpness profile of the 18-105mm is 'consistent'. With most zoom lenses, especially in the ''kit'' category, the designer must juggle a variety of factors, not the least of which is the cost of the design. Frequently a lens will be a good wide-angle performer, only to suffer when used at full telephoto; or, vice versa. This is not the case with the 18-105mm, which shows excellent performance at all focal lengths. Chromatic Aberration Chromatic aberration is present in images produced with this lens, but only most noticeably when used at its widest focal length (18mm). CA is generally well-controlled at all focal lengths, showing up mostly in the corners (this is represented by the red ''maximum'' line in our CA test results graph). Zooming out slightly reduces the presence of chromatic aberration drastically. Generally, the choice of aperture doesn't really influence the presence of chromatic aberration, but according to the test charts we do note a slight rise in CA as the lens is stopped down. Shading (''Vignetting'') The 18-105mm does show some evidence of corner shading, but its presence is fairly subtle. If you demand absolutely no corner shading in images produced by this lens, you'll have to use it at apertures of ƒ/11 or smaller; larger apertures result in some form of corner shading. Using a focal length of 35-50mm will help; these focal lengths are a bit more forgiving, and will only produce significant corner shading when the lens is used at apertures wider than ƒ/8. Distortion Distortion has always been a feature of Nikon's consumer-level zoom lenses, and the 18-105mm has not improved in this regard. There is no focal length setting where the lens has been optimized to produce a distortion-free image. The distortion profile for the lens varies widely with the focal length being used. Autofocus Operation As an AF-S lens, autofocus operation is quick and virtually silent. The 18-105mm will work on all Nikon camera bodies that support SWM (silent wave motor) lenses. Autofocus results can be overridden at any time by simply turning the focus ring. Macro The 18-105mm isn't designed for macro work, but is holds up with a respectable 1:5 reproduction ratio (0.2x magnification). Minimum close-focusing range is 45cm (almost one and a half feet) from the image sensor; from the end of the lens, you're looking at about 28cm (11 inches).