The SQ-B is a simplified version of the SQ-A. It is sometimes called SQ Basic. It was made in 1996, making it the newest camera in the SQ line.
The Bronica SQ is a 6x6 medium format SLR camera that replaced the Bronica EC as their 6x6 format camera from August 1980. The SQ is often said to mean square.
Similar to the 6x4.5 based ETR series that came before it, the SQ uses a leaf shutter-based lens design. They are not compatible with the older series of focal plane shutter cameras. The lens system has a Seiko manufactured electronic shutter with a speed of 8 sec. to 1/500 sec. plus T with the focusing helicoid built-in to each lens. The sync connector is located on the front of the camera by the lens mount. Since it's a leaf shutter-based camera system, flash sync is available at all speeds.
An interchangeable back system was incorporated that has the ability to use 120 or 220 (12 / 24) exposure film backs. The backs contain an ISO speed dial setting that is coupled to metered finders. Since the body and back need to be synchronized, make sure to wind the film crank completely before attaching the back. The film back also contains a crank, useful for setting the film start index. The main film crank can be removed to attach a winder or speed grip. The shutter release button can be locked with a twist of the collar to prevent mistaken exposures. The film back adopted some of the dark slide features of previous models. The camera will release the back when the dark slide is inserted and the release button pressed.
About lens: This is the fastest lens available for the SQ, making it an excellent choice for available low-light situations. It has tremendous resolving power resulting in edge-to-edge sharpness. This is also the normal lens that gives the closest perspective to the human eye. It is used in wedding and portraiture as well as for architectural, landscape, and commercial applications.