I have purchased a brand new lens which I have just opened today to pair with my relative new D3100. I have noticed that there is a fair amount of friction in the zoom ring as you advance from 135 mm zoom to 200 mm zoom. There is normal resistance between 55-135 mm. The resistanace is such that it can make the movement of turning the zoom lens very jerky. I am not sure if this corrects in time. I have turned it back and forth several times but does not appear to be reducing the stiffness. Anyone had a similar experience?