3.7x Frankenplena macro lens

Just a fun experiment, coupling my Z 50/1.2S to the front of my Plena using a double male 82mm threaded ring. Figuring the portion of the SD card that filled the frame was about 9.5mm wide, that equals about 3.7:1 magnification. I did try the other way around but got severe vignetting. A D-type F-mount lenses would be better suited for this purpose, as all controls would be mechanical. This setup was too unwieldy, heavy, and I did not want to put too much weight on the threads of either lens. But the result was quite good!