http://www.nikonchat.com/70-300mm-nikon/

nikon 70-300mm f4-5.6 G Lens Has anyone used a Doubler / Teleconverter on this goal effectively?
Nikon 70-300mm f4-5.6 G lens anyone has used a bender / Teleconverter on this goal effectively?
With a bender, you'll be looking through a manual focus lens yf/8-11. The approach breaker does not work, as doublers need a 2.8 or faster.
Tamron Af 70-300mm Nikon