The actual circle of illumination varies a lot even when we compare lenses of the same design, i.e. dagors, plasmats, etc. However, virtually all plasmats are capable of at least 70 degrees of coverage, and most are capable of 77 degrees or slightly more. However, the only factor I am aware of that you can use to determine actual coverage at the extreme limits for ULF work is the human factor, i.e. experience.
Originally Posted by Rick Olson
I am not personally familiar with the Fujinon L lens. Is this a tessar or plasmat type lens. If it is a tessar type the coverage should be less than for the plasmat type -W series, but it still should be enough to cover 7X17 with a couple of inches of movement.