Behold: one of the oddest cameras in my collection. I think I finally have it working properly. This is a 1920's single lens reflex, which makes eight huge 6x9cm exposures on a roll of 120 film.
The lens is an f/7.7 and there is no magnifier built in - so focusing takes a bit of back and forth going from blurry - less blurry - blurry again - less blurry (I think?) - more blurry (definitely) - less blurry. Oh yeah, and even at 1/50th of a second the mirror slap is large enough to be detectable on seismographs up to 300 miles away.