My grammar book says that if you saw the complete action you use do/get/drive: "I saw him fall off the wall." Otherwise you use -ing: "I saw him standing at the bus stop."
A native American speaker said that he doesn't agree with that and there is no difference whether you use -ing or not. He said that particularly in these situations I can use either verb without affecting the meaning:
—How do you know I took the money? —I know it because I saw you take / taking it.
—How did the woman fall? —I don't know. I didn't see her fall / falling.
He couldn't come up with a situation where this rule makes sense. But I tried to come up with such situation and he said that in this case it can be true.
I saw him eat the whole plate of pasta.
He ate everything that was on the plate. I saw him finish it.
I saw him eating the whole plate of pasta.
I saw how he was eating from a plate full of pasta. But I'm not sure whether he ate everything or not. I didn't see him finish it.
Please comment on what has been said. And give your opinion about this rule.