I have never come across anything that states that Hitler visited any of the camps, whether a concentration camp, labour camp or death camp. Everything seems to point to Hitler remaining as distant from these sorts of activities as possible.

Himmler visited the camps as they fell under his control. There's an account of Himmler asking to see an execution and becoming quite sick when it was conducted in front of him.

http://www.bing.com/images/search?q=himmler%20concentration%20camp&qs=n&form=QBIR&pq=himmler%20concentration%20camp&sc=0-0&sp=-1&sk=

There's pictures of Himmler at the camps. Nothing seems to return pictures of Hitler at any.