Film advance
Film advance is a mechanism for moving film from one spool to another incrementally one frame at a time.
Advance may be a manual process, and may be called winding, advance, wind-on and various other terms, and may use, for example, a knob, key, lever, slider or thumbwheel. For this method there must be some way of stopping winding when the next frame is reached; typical methods are the red window, or some more positive method where the camera stops the winding at the correct point. Some cameras used more eccentric methods, such as the Werra, which had a ring around the lens for winding, or the Bencini Unimatic, where the shutter release button was pushed sideways to wind, and the Voigtländer Vitessa - equipped with a plunger.
A few plate cameras (e.g. the Houghton Klito No.1) adopted a "falling plate" arrangement, where a number of plates were kept in a sprung magazine, usually behind the focal plane. After exposure, the exposed plate fell forward into a well, allowing the next one to move forward for use.
Many cameras - particularly later ones - have some form of automated wind-on, triggered by the shutter release. These use a clockwork mechanism (e.g. the Robot cameras or the Kodak Instamatic X-45), or an electric motor. On a number of SLR systems, there were add-on motor-wind devices produced between the 1960s and 1990s.
