Miniature Speed Graphic (2 1/4" x 3 1/4") sometime in the 1940s.
I bought this one from KEH around 1980 when they used to go out to camera shows to sell gear. This one is unusual in that it is upgraded with a Graflok back.
I have an old Kodak Vest Pocket that I picked up in a London flea market. But my oldest camera that I have actually used is my old Pentax Spotmatic that I must have bought in 1976, and was a companion on many adventures, like a trip around France by train.
Like most of the cameras I have bought since, the EM5 has gone to a new home, but I have kept the Pentax for sentimental reasons-
…and did anyone else have that amazing contraption of rods and clamps and screws which coupled the shutter release on the lens with the shutter release on the body?
The release on the lens caused the aperture to stop down just before the shutter release on the camera was triggered, provided it was correctly adjusted. The lens aperture had to be manually opened up again after each shot.
All a bit crude in comparison to todays fully automatic cameras, but still a big step up on fully manual cameras.
Though I have many Exaktas (nine!), the one which I mostly used was the later VX1000 which had an instant return mirror and a fully automatic diaphragm (Zeiss f/2 Pancolar lens - which I also regret parting with).
I don't know of a scanning back that fits in the gate of a 2 1/4 x 3 1/4 camera. The Betterlight backs fit 4x5 cameras, and slides in like a film holder.
There are graflok backs for 4x5 too...
Smaller sizes of single sheet film cameras are pretty much obsolete, so it's unlikely anyone will make expensive LF extras that are only for quarter plate/sixth plate etc.
I might see if I can fit a friends Bronica fit digital back to my Ruby Reflex Junior, as I've not managed to find the right plate holders for it yet, despite getting a job lot half a dozen different types that are all quarter plate (including several by the same manufacturer as the camera). The range of film/plate holders used back in the 1930s is astounding.
Yes, the 4x5 Speed Graphic I used to have had a Gralok back on it. I miss it in some ways, especially the Polaroid back I had for it, but on the other hand I just wouldn't shoot 4x5 anymore, so the Miniature model suits me just fine. I have all the size variations available for 120 film. I also have a 220 back but this is kind of useless these days. I bought sheet film holders for it when I got it, maybe at the same show, and I have the proper tank and film carriers for developing it at home. But roll film is so much easier! If you ever find the right film holders, Ilford, Adox and Freestyle's house brand, Arista, still make 2 1/4 x 3 1/4 sheet film. Also, once a year Ilford does a run of truly oddball sizes up to 20" x 24", for (quite) a price of course. It's called "ULF" Ultra Large Format. In any case, the price is another reason for me to stick with roll film...