I'd love to see the info you refer to as it would be educational for me. From what I know, it'd be impossible for these lenses to have sample-to-sample variation of a human-detectable amount under normal conditions. Maybe if you're shooting test targets from a fixed tripod and looking at individual pixels? Yet even then, the entire point of focus breathing is that you're comparing the size of something when it's in focus to when it's NOT in focus... and how can a human eye make that comparison accurately when the out-of-focus shot is blurred to the order of 50 or even 500 pixels?? Tolerances of the parts in the lens are far, far below a millimeter and even what little variation there is has a lot of adjustments.
Again, happy to believe I'm wrong and you're right, but I'd like to see the specifics of what you're referring to. Is it side-by-side apples-and-apples comparisons? Or is it just some guy who had two copies of a lens and is reporting the old one had a different amount of focus breathing, without giving apples-and-apples examples?
