Larger pixels is the primary factor. The signal needs less amplification - so there is less heat and noise generated - much like audio in some regards I'm guessing. More pixel density gains resolving power but at the expense of noise and lower sensitivity. In daylight these things don't collide for images that are relatively small files. It's astounding how small the sensor and lens systems are in camera phones - and the superb images they can generate with the power of advanced processing.
If you print a file to a 20x30 inch print, and view it from 6 feet or less the defects and nuances become clearly visable. That's when the bigger sensors really show their advantages in image quality. Viewed digitally, a well exposed image file from a good phone or a FF sensor is usually barely discernable unless your pixel peeping or the original image is severely cropped
Mostly, yes, but it all depends on use case.
Here’s what I want: a print that even when approached and viewed closely does not undermine the illusion of unlimited detail—that the only reason more detail can’t be seen is because the viewer can’t get closer.
Any camera/lens/capture system can create that impression up to a certain print size. I can make snapshot-sized prints from an iPhone, or prints three feet by four feet from my 645z while maintaining that illusion similarly.
That’s my objective for resolution and detail, and I’ve been chasing that objective for nearly 50 years, using cameras up to 4x5”.
My objective for tonality is to avoid any impression of tones being discontinuous. That is actually more difficult than the resolution and detail. Software generally wants to smooth over noise and increase the appearance of edges. This creates the impression of sharpness with smaller enlargement ratios. The more software processing (in camera or in post) that is required, the smaller the resulting print can be and sustain the illusion of continuous tone when viewed closely. That’s no small accomplishment.
My iPhone photos look great on iPhones, and only okay on computer monitors—most of those are documentary and it’s good enough. A 16x20” print? No way. I don’t go larger than 12x18” prints with my Canon 5DII, because colors wash out and the limits of detail show themselves. My big Pentax will much more than double that, but the Canon is certainly not recent tech.
Bigger sensors support both of my objectives in part for the reasons you mention, but only in part. Newer small sensors attempt to do so mostly by use of greater software power, and to some extent by improvements in the sensels themselves. But the worry about aliasing, even with very high sensel density, and use a filter to cut off detail near the Nyquist limit, just as we do in audio.
But the 33x44mm sensor in my 645z, which came out in 2014 but used 2013 sensor tech, does it better than my wife’s Nikon D500 DX-format camera, which came out three years later. That’s true even in low light and high ISO. The sensel density is high but the cells are larger and either avoid the aliasing problem or leave it to post-processing, which means no AA filter.
Lenses are part of the problem—a big part. I can attain my objectives with most lenses Pentax made for medium format, even film-era lenses now ridiculously cheap in the secondary market, when used carefully. The lenses needed to get the most out my wife’s D500? Bring your checkbook.
So, technological advancements do not replace the importance of size, at least not a generation or three, because sensor tech is only part of the problem in the real world.
(This isn’t an issue related to mirrorless or not, of course.)
Rick “who actually makes bigger prints, and isn’t measuring outcomes based on pixel-peeping” Denney