Originally Posted by sandholm
Well, its not me its the http://www.allenrumme.com/lensdb/DBIntro-1.html and the 12 lenses I have are correct listed in the database.
If you doubt, check which source he got it from and ask them.
I checked. You misread the table. He does indeed report that the 30" TTH Series IX covers 20 x 30, but at 1:1. At infinity it covers 15x20, i.e., 45 degrees.