sorry to open old discussions,
but on a previous thread, you suggested that if one focuses an enlarging lens wide open and notices the edges unsharp of the easel, all one would have to do is close down the apeture and the edges would *snap* into focus.
Since that discussion I have consumed quantities of beer to wrap my head around that statement .
Are you of the same opinion?????
If so I will drink some more beer and try to understand.