#1, the monkey will not use the Leica as a camera.
#2, the cameras will have decayed to nothing by the time the monkeys evolve into something that can intelligently use a camera.
#3, there is no way a monkey will reload the film in a Leica II. Heck, even humans have a hard time with it. How Changing Film Cost One Photographer a Chance at an Iconic Vietnam War Photo
Wired Magazine: Monkeys Don't Write Shakespeare