Speaking of folders, some years ago I was rummaging around in an old house my parents had deeded to them, and there were several old (and I mean OLD) cameras around, most of which were cheap variations on a theme.
But there was one I latched on to - a Welta 35mm that I think dates from around the late 1930's. It pretty closely resembles some of the old Kodak Retinas, and the thing is built like a brick. (No resemblance to the other one, Argus C-3!!).
This one has a Schneider-Kreuznach Xenon f/2 lens with stops to f/16, shutter speeds 1 - 1/500th plus T and B. It is strictly scale-focusing, and there is no sign of any kind of flash provision. I've tried a couple of rolls of print film in it, and with the Schneider lens, it comes through quite nicely. Even has a sort of parallax corrector on the viewfinder, and there's also a cable release socket. The only thing that doesn't work is the frame counter, but with 35mm, you don't have to guess when you reach the end. Of course, you then have to go through the rather laborious process of rewinding. (Funny how we have sort of forgotten about that one!) All in all, a rather interesting piece for that long ago.