A TC actually will help, but tubes will help even more. A TC wont actually increase the MFD, but it will give you a 2x(or 1.4, 1.7 etc) crop, so higher magnification. I use the TC with my Sigma 50/2.8, which does 1:1 macro reproduction, it can focus to just a couple inch. With even a short tube, you should be able to focus…