Kerry, in addition to the official 46° coverage specs (calculates to 510mm diameter for the 600mm lens, 636mm for the 750mm lens, and 850mm for the 1000mm lens, all at infinity) there are the mysterious "infinity" circles published in a single typed page by Docter: 585mm for the 600mm lens (52°), 715mm for the 750mm lens (51°), 895mm for the 1000mm one (48°) - this is supposedly all for the barrel versions wide open (!) at f/9. Stopped down, the coverage increases a little further to values up to 57°.
Originally Posted by kthalmann
Disclaimer: I have not tested these values, these are values from an old Docter leaflet.