Last year we explored both Upper & Lower Antelope Canyon. Upper Antelope is guided only - and the only way to describe it is as a zoo. It's incredibly beautiful, but the tour companies run hundreds of people at the same time through the small slot canyon. The amazing light beam photos you see can be deceptive - as they almost all involve a brief moment of holding the flood of people back for a quick shot.
We had an opportunity to experience Upper Antelope in a different way - though a small night tour. It was just us with 1 other photographer - and amazing peaceful.
Our guide was Lionel Bigthumb - an incredible guide and accomplished photographer in his own right. We highly, highly recommend him out of the multiple slot canyon guide options in Page, AZ. http://www.navajoantelopecanyon.com/tours.html
Looking at the entrance - with the interior light painted by our guide