Out of focus? I don't know about you but I find the black hole "edge" in the simulated images in Interstellar quite sharp. (Or are you talking about resolving

Out of focus? I don't know about you but I find the black hole "edge" in the simulated images in Interstellar quite sharp. (Or are you talking about resolving matter/light near the event horizon? In that case I agree – one won't really resolve any structures anymore due to light getting bent and redshifted in a myriad of ways.)