Yes you are correct on the lense compatability with the D40. Which kit did you get that would help. The D80 stock kit lense is the 18-135 lense and, is $1045 at B&H so, then you would be left with some money for another pice of glass or, somethingelse. Maybe an extra battery or, the 50mm f/1.8 which is a great little lense for the money.Now do you mean will work with the d40 or autofocus? Cause the above post is right unless you mean autofocus then a lot of lenses wont autofocus. But they will on the higher end cameras. Someone can correct me but isnt it the AF-S and AF-I lenses that autofocus with the d40?