All this reminds me of an old RollsRoyce story, Someone wrote the factory and asked: I am interested in buying an "X" model of your cars. How many horsepower does the "X" model's engine have? The answer came back with one word: "enough". If my 35mm cameras can take "sharp" 11 x 14 prints, they are sharp "enough" for me. If I make a 4x5 picture and print it to 11 x 14 also and it is sharp also, then it is sharp "enough" for me. I am the only one those formats and lenses have to be sharp "enough" to please..........Regards!
That’s true. Photography is a system, and in any system the final results will be determined by the entire system, and not just one component of the system. Any hypothetical answer relies on various assumptions, many of which may not be practical or even possible in a real world scenario. Beyond that trying to achieve ideals in a real world problem can be expensive and fruitless. So the better option here is to consider what practically can be achieved by the means available to you.
In the OP’s case, he’s using a flatbed scanner. That’s going to be the largest limiting factor. And no 35mm film, no matter what conditions it was taken under, will ever be able to achieve the resolution possible from a scan of any 4x5 film, no matter how grainy. It’s not even close enough to warrant a test.
For me, I look at what’s possible given my means. And in my experience, I can’t print larger than about 8x10 from any 35mm film without seeing grain. Sometimes it’s not objectionable, and you can print larger without having grain be a problem, but it’s still there. With 4x5, I can print any size my darkroom will handle (16x20) without ever having to worry about grain. Same with scanning negatives, only getting an 8x10 worthy scan from a 35mm negative requires a better scanner than a flatbed, and extensive post processing work.
