The Nikon D40 and D40x were the first Nikon cameras without a built in auto focus motor. This has now been followed with the D60 camera. This means that any lens used with the D40 D40x and D60 will need an auto focus motor built into the lens. Many Sigma lenses have been re-designed to incorporate a built in motor, allowing autofocus when used with all Nikon cameras, including the D40 D40x and D60.
This lens is fully compatible with the Nikon D40, D40x and D60 camera which require a built-in motor.