Hi,
I bought a Nikon D80 two years ago for digiscoping purposes but then moved to an F2.8 Prime lens and these work well together, however if I use a converter the quality just disappears.
Even really close up with a 1.4 converter I cannot get a sharp image and using the 2x converter is only an option for a record shot.
I have spoken to Canon owners who say that theirs work properly together but finding a Nikon owner is rare and I begin to suspect that the reason is that their quality leaves a lot to be desired when adding a converter.
Can someone enlighten me as to where I may be going wrong please
Many thanks

that's typical, teleconverters ALWAYS degrade original lens' image quality, whether Canon or Nikon, or whatever brand.

if you want to get closer focus and retain lens IQ use an extension tube.

another option is to get a reversing adapter; a reversed lens makes an excellent macro lens!