The camera used to take photos on the swing set didn't use 35mm film (it was a 126 film camera, which uses cartridge film, in a 4:5 aspect ratio), but the prints that were returned were a 2:3 aspect ratio, and the negatives were 35mm.
At around 1:07:29, while Rachel is screaming and being grabbed and lifted to a table by the locals to be sedated, she is still concerned with decency where she makes sure her legs are covered by her dress with her left hand.