I was just playing about with a 2xTC and some tubes and a 28mm reversed.
The screw is 3.5mm and the shot is a 100% resize, and i think the frame was around 5mm, i always thought i had a steady hand but at these high mags the scene was bobbing up and down in my viewfinder, you have to respect these MPE users because its crazy over 3:1
...

