In the past I have proposed a theory about this enigmatic mistery. Or perhaps it's just inexistent.
I have said that capture of real life in a 2D medium like the one that happens in film or digital sensor capture inside a camera obscura is somehow analog to capturing real life sounds with a recording medium like a vinyl disc or a usb pen drive.
All recording methods of sound or image recording go through different stages of conversions. Inside these different conversions there's always one that degrades the most the fidelity of the original information. It is compression. In real life, sounds come from myriad of different sources. Once these sounds are emitted, the recording medium puts them all together in a relative minute storage. A piano will sound exactly as piano as long it remains a piano. Its recorded sound will be only an emulation.
In analog sound recording, the bigger the recording medium, the better the fidelity. Technology made these smaller and smaller while keeping about the same degree of fidelity. When digital showed up, we were announced the advent of a sound recording technology that was meant to be 100% faithful and that infinite copies were possible because a one was always a one and a zero was always a zero. As we all know, this never happened. Then mp3 came to scene with its sophisticated compression of redundancies that could be fully restored during playback by decompression. No such thing. Once the original got compressed, the quality got degraded beyond fix.
Well, I believe that image capture either analog or digital has in many ways similar issues.
Let me explain: When I'm capturing a real life scene of a street perspective, what happens is that I'm compressing all that visual information that lies in hundreds of meters into just an inch or four. Most of the original information in real life is likely to be beyond the resolving power of the human eye but this is what constitutes the solid image. All this information is lost for good. When reviewing the capture, this information is enlarged leaving empty spaces of information that become solid blacks and washed-out highlights.
The bigger the capture, the less compression there is, permitting little chunks of detail to form the extra dynamic range some people see in bigger formats.
In short, the smaller the format, the more compressed the original information becomes. At more compression, more lost.
Putting super megapixels in very small sensors is analog to using MP3 for music storage.
The other way to see this, is to call it the old fashion way: Tonality.
Tonality is nothing but smooth gradations from shade to shade so subtle that the human eye can't tell. Once a smooth gradation is compressed to a fraction of its original size, the smoothness becomes, well... less smooth.
I know, this is harder to explain than it is to think about it. On the other hand, it is everybody's knowledge. I can't find a better way to explain myself, besides english is not my native language. Enough excuses.
As a last try, I'd like you to think of Selections in Photoshop. We all know the trick that once a selection is done, sometimes little chunks of selections are to be cancelled. By using Modify>Contract, we make the selection a little smaller. But then, using Expand we get the selection back to its original size but those little chunks don't come back.
As we can see, reversing size modification can produce a different outcome. Going back to Mr. Sexton, 4X5 compresses less the original information while keeping those random little chunks of information that constitute detail. Detail in shadows and highlights is called dynamic range. Detail in the shades in between is called tonality.
In absolute terms, dynamic range is latitude, not resolution. So, my analogies don't fully explain the phenomena (for believers). But somehow I believe, that shrinking real life not only diminishes resolution but also diminishes dynamic range by lost of light recollection and compression of the information.
I hope I didn't bore you.
In an article by Richard Sexton he writes: "Anyone who’s compared the tonal scale of 35mm film to 4x5 film can fully appreciate what additional dynamic range can achieve in critical situations."
If the same exact film type were used in both the 35mm and 4x5 cameras, I would expect the dynamic range of the images to be the same.
Does anyone agree with Mr. Sexton's statement; and if so, could you explain why the image taken with the larger 4x5 would capture a greater dynamic range?
Thanks in advance,