Many genre's of art have a "folk art" subsection that's less refined than fine art but still clearly an expression of creativitiy and demonstration of talent.  Is there an equivalent in photography?  Any examples?

Uhm, maybe the "street photography" genre. Not sure if its what you're looking for but Henri Cartier-Bresson (I hope I'm not butchering the name) was pretty darn good at that.

This might qualify. I know it's heavily debated whether it's art.

http://www.edelmangallery.com/adams.htm

oops