D80 Back focus?
I recognized that my D80 was not accurate with the 18-70 AF-S DX kit objective. In my portraits, the faces weren't sharp, after good focusing.
I made some test (in low light, with sb-600 flash):
In 70mm it has a little back focus, but if I decrease the focal lenght, the back focus is increasing!
It has a FRONT focus in 300mm, it is accurate on 180mm, it has a back focus under 150mm.
So, it seems it is accurate only in 150-180mm. What should I do?