The Sigma 70-300mm 4-5.6 DG Lens is the ideal compact and economical choice for a telephoto zoom lens. By incorporating an autofocusing motor into the lens itself, it can now autofocus with all Nikon DSLR cameras (including the D40, D40x, etc.). In addition, with the motor built into the lens, focusing will be quieter and more responsive. Capable of macro photography, this lens has a 1:4 maximum magnification at focal lengths shorter than 200mm, from 1:2.9 to 1:2 at focal lengths between 200mm and 300mm, and 1:2 maximum close-up magnification at the 300mm focal length.