
Posted: Mon Jun 02, 2008 9:59 am
John, not to quarrel with Georges' reference, but my friend Eric Beltrando has calculated performance for Dagors and Boyer's dagor type the Beryl. See
www.dioptrique.info .
Eric tells me that although manufacturers, e.g., Boyer, claim that the lenses will cover 85 degrees at f/22, in fact 70 degrees is more nearly correct and that for stringent applications, e.g., repro cameras, 50 degrees is all that one should expect. There have been acrimonious discussions of the LF forum about Dagors' coverage; go there and search for lousy Dagor if you want a good laugh.
IMO coverage is in the eye of the beholder and you'll have to ask the lens what it can do. If I had your lens I'd use it on 2x3, possibly 3x4, not 4x5.