Quote Originally Posted by Peter De Smidt View Post
A fixed magnification rig does not require using a macro bellows unit. I use rigid extension tubes with integral mounting feet. The tube(s) are bolted to a long Arca plate along with the camera. This is simpler, lighter, and sturdier than any bellows unit. I do use my PB-4 to figure out extensions for given magnifications.
I don't use a macro bellows unit either. I use a Sony E-mount to M39 focusing helicoid. Similar to the one shown here, except this one is E-Mount to 42. These are sold under several brand names, though they all may be made in one place. I purchased mine on AliExpress for $21, plus $4 shipping. I also have one for the Fuji GFX mount.

https://www.amazon.com/Fotasy-Mount-.../dp/B01HG3RYR0

Sandy