billnikon wrote:
First, you posted in the wrong section.
Second, no teleconverter ever produced improves image sharpness.
Third, combining teleconverter's really makes sharpness suffer, as seen in your images.
Forth, I use a 600mm f4 without any converter on a full frame mirrorless camera that I use for my wildlife photography.
Fifth, I never use teleconverter's because of the reasons I have given.
Sixth, Good luck and keep on shooting until the end.