I have a Diana F+ Lomo (120 mm native). I recently bought the plugin to make photos with 35mm films.
I mounted the film correctly, but I had problems while taking photographs.
It was a 36 exposure film, but when I took the pictures and moved the film forward, advancing one by one every photo, I noticed I finished the film when the counter was on 18. When I developed the film, I had photos cut in two parts, with black parts too.
It happened on every photo I took, I moved the film too far forward. But I didn't know why, because I think I followed the index counting the photos. But at the 18th step it was impossible to go on, because I had already arrived at the end of the film.
Does somebody know what I did wrong and how to avoid this next time?