Originally posted by Raylon So basically a 50mm prime built for FF should be the same as a ~35mm prime on APS-C. But renaming all the formats would be very confusing, so everything is done to a single standard.
You were doing well until you got to this, and then it got confusing again.
I think what you MEANT to say above is:
"So basically a FF 50mm prime mounted on a FF camera will have the same FOV as a ~35mm prime on an APS-C camera. But renaming all the formats would be very confusing, so everything is done to a single standard."
But your basic sentiment was correct: 70mm is 70mm no matter what format the lens is intended for. It's the sensor that crops FOV, not the lens.