The values are only valid for the camera body the lens was used on, because that camera and its Bayer filter/AA Filter/sensor/processor are part of the value you see.


The MTF 50 numbers are NOT for the lens itself, they are much higher for just the bare lens, the body drags the MTF down a lot.


Unfortunately, no one posts numbers for just the lens itself, the test equipment is very expensive to test just the lens. The Canon MTF graphs may be from actual barelens tests, but I believe some say they are computer generated.