Did Hitler ever know the full extent of what was going on in the concentration camps?

I Am in now way supporting Nazism or Hitler but am simply asking was Hitler himself actually aware of what brutality went on in those camps. Hitler is always portrayed as some sort of mythic beast, a manifestation of complete evil. But He was indeed human as you or me, he had feelings. After all was is it not Heinrich Himmler who was left in charge of all that, Hitler was the chancellor/dictator, was he not much too busy with leading a nation through a war than to be commanding how the camps should operate? I know extermination was not his first choice as well.But like i said above i do not support Hitler, the things he allowed to happen were horrible but did he know to what extent how horrible it was for the jewish and other minorities. Its not like he did the things himself. Please answer in all seriousness, this is a serious question.