>>4137217BECAUSE
YOUR AF POINT
DOES NOT
CONSIDER
THE
ACTUAL
SHAPE
OF
THE
DEPTH
OF
FIELD.
It's just a phase/contrast detect algorithm finding a single sharp edge in your AF area. That's it! Between two lenses, especially different makes and models, even if your AF point is the same, the things actually in focus in the photo WILL NOT BE.
You are talking about filtering and sending light
I am talking about actual lens characteristics. Field curvature. Internal reflectance. Sharpness. You can also talk about coma and astigmatism if you'd like. The more "natural" it is to the typical flaws of the human eye the more apparent the "lifelike rendering". These qualities also vary between different copies of the same lens.