I've been packing a pre-1950 Mamiya 6 folder for a couple of years now. It fits in a jacket pocket, and the cargo pocket of my pants or shorts. I've always been a fan of square negatives, so any folding 6x6 gets my nod. I have also been a fan of Kodak Tourist cameras, the originals with Anaston 105/4.5 lens on flash Kodamatic shutters, 6x9 from a package not much bigger than my Mamiya 6, and sharp. The only drawback with them is zone focus, but once you get the hang of using them, makes life easy.