This addon uses a single function to set the cameraDistanceMaxZoomFactor CVar to tested maximum.
There are no options or toggles; it was specifically uploaded to avoid these options.
If you desire this type of functionality I highly recommend adding it in yourself and creating your own CurseForge project; you can download this addon to start your project, just edit the title and author, you can do it!
This can be done with a macro or script, but an addon can simplify UI synchronization over multiple realms and characters.
See macros below:
C/TBC:
/run ConsoleExec("cameraDistanceMaxZoomFactor 3.34")
/run SetCVar("cameraDistanceMaxZoomFactor", 3.34)
Retail:
/run ConsoleExec("cameraDistanceMaxZoomFactor 2.6")
/run SetCVar("cameraDistanceMaxZoomFactor", 2.6)