Quote Originally Posted by mhayashi View Post
Some brands yes, some others not.
Busch doesn’t follow this rule in some series in a give period.

Serial groupings evolve and shrink over time, given brands.

Here is the catalog.
http://www.cineressources.net/consul...b/o000/215.pdf

Projection lenses are listed in this catalog.
Thank you so much - that's an excellent source!

Indeed, it seems quite weird how Emil Busch made these distinctions and things aren't getting any easier with all the different names the company used...

I'll certainly have to take a close look to find out the different systems behind it all, but at least I think I've got enough relevant material now to figure part of it out.