Toronto. Around the turn of 1900, a number of Leaf shutters emerged, all at the front of the camera. For efficiency, the shutters were usually mounted between the lens elements next to the aperture diaphragm.
Bausch and Lomb made a number of shutters including the popular UNICUM model shown here at left top. A hollow rubber tube could be pushed on the base of either cylinder so a rubber bulb could be used to trigger the camera.
Optionally the operator could squeeze the lever at the top of the right hand cylinder. The various shutter speeds are set using the chrome wheel on the top of the shutter and lens assembly.
Most inexpensive cameras, and some high end models used leaf shutters. The benefit was slower speeds than the focal plane shutters of the time offered. Almost all Kodak cameras used simple self capping two leaf shutters. Box cameras often had time and instantaneous (about 1/25th second, fast enough for hand held shots) settings with more expensive folders giving a variety of instantaneous settings up to 1/100th second.