Leica's slow-speed Barnack body — the Model F, coupled RF, 39mm screw, cloth shutter, 1933.
The Leica III, or Model F, arrived in 1933 and extended the Barnack line by adding slow shutter speeds and a dedicated slow-speed dial on the front of the body. It sat above the Model II in the range and became one of the most widely used pre-war screw Leicas.
It is a 35mm coupled-rangefinder camera taking 39mm screw-thread lenses, with a horizontal-travel cloth focal-plane shutter offering a wider speed range than the II thanks to the added slow speeds. Focusing and framing use separate rangefinder and viewfinder windows, there is no built-in meter, and the shutter is fully mechanical and battery-free.
It suits photographers who want the classic twin-window Barnack experience with slow speeds for low light, plus collectors of pre-war Leicas. The magnified rangefinder window aids precise focusing, though the two-window workflow is slower than later single-window models.
Check rangefinder patch contrast and vertical alignment, and confirm the front slow-speed dial operates cleanly across its range. Test slow speeds for accuracy, inspect the cloth curtains for pinholes and capping, and look for haze in both finder windows. Confirm smooth film transport and a clean screw mount.