Dude that's by far the best explanation I've had. Things are making sense now.
I fully understand why at its lowest point it crops by 1.5 causing a 10mm to be 15mm but how does it amplify when a lense is closed all the way? Like how does a 200mm become a 300mm? Don't know if that question makes sense? Also, does that still mean that you're going to get the same sharpness you would from a 200mm full frame and 200mm (300mm) crop frame?