I'm told that this 10-inch Wray APO Lustar is the English version of
the Goerz Artar. I can't verify that, but I can verify that it covers
at least 8X10 inches, and possibly more -- I don't have a larger
camera to check.
APO (apochromatic) lenses are highly corrected for color, but if
needed, it has a slot for filters, which should be about 39 to 41mm in
diameter. The filter slot closes to keep light from entering the
lens. Stops are from f10 to f90 (!)
http://cgi.ebay.com/ws/eBayISAPI.dll...m=330023677145