The Graflex Series B is a large format, SLR camera produced by Folmer & Schwing between 1923 until 1951. The Series B looks like a large box camera, but it has a folding viewing hood atop a ground glass focusing screen in the top of the camera body. The rear of the camera features a focal plane shutter with speeds as high as 1/1000. The user could set various curtain apertures and tensions to achieve a number of different shutter speeds. The front of the Series B is equipped with a simple standard with threaded opening for screwing a barrel lens into. The standard could be moved into or out via a geared rail to focus. Internally, the bulk of the camera body was taken up by a large reflex mirror that allowed true through-the-lens viewing.
The Series B was produced in a few different film formats, including 3-1/4 by 4-1/4", 4x5" and 5x7".
There was the standard Series B as well as an "RB" model which had a rotating back.