Hi people. Just wondered if any one out there uses the Nikon 500mm f4 VR 2 with the 1.7 converter. I have been using both the 1.4 and the 1.7 and can not notice much difference. In fact I would say that the 1.7 is sharper which goes against all i've read. Any comments would be appreciated. It is used on a D300s. Thanks. Omllett.