Oh my,
You can buy a box of those old folder lenses from ebay that are removed from their original bodies.
Stick one of these on an extension tube with the mount that you want to use, EF, F, Pentax K, Hasselblad, whatever, and there you go, instant portrait with lots of "petzval" bokeh and swirly effects. Use your feet to focus, and forget about infinity, but you don't care about that for the type of photography that the video suggested anyway.
TIP: For more gentle effects -- and in my eyes, more beautiful, use a real medium format cameras, I use my Bronica S which allows me to focus using the camera, not my feet.
If I have access to a Pentax 645 Digital, I would use that.
No need to go to the trouble these people are putting themselves... unless you *have* to have a brass cylinder in front of your camera.