As photons don’t scale, smaller photosites just get noisier, which is why cameras in iPhones croak in the dark.
Mobile phone cameras croak because their sensors are small, not because their photosites are small. The total amount of noise in an image is much more a function of sensor size (by orders of magnitude) than of photosite size.
Medium format pixel counts continue to rise to pointless numbers, with the unsurprising result that noise becomes a problem. Don’t worry, you can get noise reduction software that reduces the noise, and the resolution, again.
And it's no more true for medium format than it is for the tiny sensors in mobile phones. In fact, smaller pixels give you increased spatial resolution that you can then either keep (when lighting is good) or trade off against reduced noise in a way that is better than simply averaging the pixel values (as larger pixels are effectively doing).
Biting the hand that feeds IT
