Okay, I was browsing around trying to find some details on an old lens I was given a couple of years ago. The bay of e had one that the seller claimed could cover 20x24. The difference is my lens is marked for stops up to f/128, and the seller states that theirs would only go to f/90. But what coverage could I reasonably expect from it? I also have a nikkor 420mm mounted to the same board as it, with the f-stops synced together. What kind of coverage could I get from the 420mm as well? I was thinking of starting a camera build to use either one of these lenses, so I wanted to know what format I could cover. Thanks in advance.