In addition to what Snapshott has already written, the Nikon TC’s will not fit on your lens without some major modifications ( you need to grind or cut off a tab). If you go to the Nikon USA (http://www.nikonusa.com/Find-Your-Nikon/Camera-Lenses/index.page?) page on lenses and bring up any of the TC’s you will see a list of lenses that they will fit. For instance the TC 14E II will fit the following lenses; 200mm f/2G ED-IF AF-S VR, 300mm f/2.8G ED-IF AF-S VR, 400mm f/2.8D ED-IF AF-S II, 80-200mm f/2.8D ED-IF AF-S ,70-200mm f/2.8G ED-IF AF-S VR Zoom, 200-400mm f/4G ED-IF AF-S VR Zoom, 300mm f/4D ED-IF AF-S, 500mm f/4D ED-IF AF-S II, 600mm f/4D ED-IF AF-S II. That’s only 9 lenses.

A number of people have asked about the 70-300VR and the people who have tried it have pretty much stated that you can get as good, if not better, results by simply cropping your picture, and unless the light is very good auto focus becomes very iffy.

If you still want to try, your best bet is the Kenko 1.4x Teleplus Pro 300 DG Teleconverter that sells for approx. $200. With the 2X converter you lose too much light and AF rarely works even in good light.

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Brooks
http://bmiddleton.smugmug.com/