The Diana+ 35mm Back is completely interchangeable with a simple snap. The back has four different "frames" with which you can select the appropriate format you want to shoot in.
It is important to remember that the back (when connected) disconnects the shutter release and film advance. This gives you the freedom to shoot as much or as little as you desire. In this way, you can create some incredible images. The possibilities are limitless and and only limited by your imagination.