Antelope Canyon is a popular location for photographers and sightseers, and a source of tourism business for the Navajo Nation. Private tour companies have been permitted to offer tours since 1987. It has been accessible by tour only since 1997, when the Navajo Tribe made it a Navajo Tribal Park. Photography within the canyons is difficult due to the wide exposure range (often 10 EV or more) made by light reflecting off the canyon walls.[5]