How about . . .
28:1 with a single (Nikkor) lens and no TC?
http://www.dpreview.com/forums/post/21952208
(Direct imaging of diffraction rings.)
Roger Cicala reveals winners of First Annual Photogeek contest
Posted by Chris Roubis on 3rd, Dec, 2013
Source Article from http://www.dpreview.com/news/2013/12/02/roger-cicala-reveals-winners-of-first-annual-photogeek-contest
Started out doing photography at the age of 6 using an uncle's old 1940 kodak brownie box camera. At 15 years of age, I decided to buy my very own 1975 Praktica SLR camera. I now shoot with a Nikon D850. I do unpaid TFP and commercial paid work.