lenses for aps-c question

I understand that, but what I was referring to was aps-c lenses (like sony's newest 16-50mm f/2.8). From what I read, that lens (16-50mm f/2.8) is specifically designed for sony's aps-c size sensors. The link just tells me what happens when you mount a full frame lens on an aps-c sensor, and how it compares to ff. That's not what I was asking.