How strange is this... I've tried the lens this evening on a Nikon D90, and a D3... and it works fine on both.... Does this mean the problem is now in my camera? Sigma have replied saying "This will be because the camera has no built in AF drive it requires HSM lenses to function unfortunately this lens is not HSM so will not work with the D40/60/3000/5000 but every other Nikon." This can't be right, It should still work. It should just not have the Autofocus Feature. I phoned Nikon support today and they said that if I sent it in, the camera would be tested to work with Nikon lenses... Because the fault is with a Sigma lens makes it My problem... Not theirs!