this is related to the geronar thread....If the 300mm f9 geronar gives a circle of 340mm aT F22, will this increase much as I stop down further. I would imagine it will be used at f32 more often than not, as f16/22 is where my 5x4 lenses see most use. I know some designs do not increase coverage much below a certain f stop (peak at f22 or so), what about this triplet design lens? Certainly more coverage would be handy, though as I am a field user I dont need to much coverage. 360mm or so at f32 would give more wiggle room.
How can one tell if a perticular lens will continue to pick up coverage as stopped down or not (I have heard that many older deisgns like the dagor/g clarong continue to gain coverage, whereas many more modern ones do not and in fact may decrease???). Are there rules that can be applied to particular designs?