The Tamron AF18-270mm f/3.5-6.3 Di-II VC LD Aspherical (IF) Macro Lens is a 15x high power zoom lens designed exclusively for digital SLR cameras using the more compact (APS-C) digital size image sensors. The focal length of this lens is equivalent to approx. 27-405mm in 35mm format. Designed as an "all-in-one" lens, it will meet almost all photographic opportunities without changing lenses.
The VC (Vibration Compensation) mechanism allows the use of shutter speeds that are much slower than otherwise possible, with no perceptible increase in image blur. It automatically detects movement of the camera and compensates for camera shake when shooting a moving object. This feature is a must in a lens with this long of a focal length.
The AF18-270mm lens, made for the Nikon digital SLR system, incorporates a motor built into the lens itself, which gives it the capability to autofocus with all Nikon DSLR cameras (including the D40 and D40x). In addition, with the motor built into the lens, focusing will be quieter and more responsive.