According to David Bordell continuity has intensified in Hollywood cinema because there has been new advancements in style and techniques in filming that have evolved over the years. Advancements such as more rapid editing, bipolar extremes of lens lengths, more close framings in dialogue scenes, and free-ranging camera.
More rapid editing:
Between 1930-1960 hollywood films contained between 300 and 700 shots and the average shot length (ASL) was around 8-11 seconds. In the 1960s, American and British filmmakers were experimenting with faster cutting rates: ASL around 6-8 seconds. 1970s, most films had an ASL between 5-8 seconds and around a thousand shots. In the 1980s, ASL averaged around 4-5 seconds and 3- 4 for those movies influenced by music videos and in action pictures. Most films were around 1500 shots and near the end of the 90s, movies contained 3000-4000 shots and an ASL between 3-6 seconds. "Some action sequences are cut so fast (and staged so gracelessly) as to be incomprehensible". Most scenes include conversations and shot/reverse-shot exchanges are applied and the eyeline match of the characters can serve as an establishing shot so longer shots are not needed.
Bipolar extremes of lens lengths:
1910s-1940s, the normal lens had a focal length of 50mm, longer lenses (100-500mm) were used for close ups and swift action at a distance. The 1930s relied on shorter lenses (25-35mm) for good focus in several planes or full shots, which became the normal lens. 1970s, wide-angle lenses provided establishing shots, medium shots, and close-ups. "Even more filmmakers turned to the long lens. Thanks to influential European films like A Man and a Women (1966), the development of reflex viewing and telephoto and zoom lenses, an influx of new directors from television and documentary, and other factors, directors began to use a great many more long-lens shots". Long lenses could save time and multiple-camera shooting. The long lens can frame close-ups, medium shots, over the shoulder shots, and establishing shots.
More close framings in dialogue scenes:
1930s-1960s, directors played out scenes that cut off actors at the knee or mid-thigh level, which called for lengthy two-shots. Two-shots were replaced by singles only showing one person. The filmmaker must find ways to emphasize certain lines or facial reactions in scenes that rely on rapidly cut singles. "in many films the baseline framing for a dialogue became a roomy over the shoulder medium shot. So the filmmaker began to work along a narrower scale, from medium two-shot to extreme close-up single". A reestablishing shot may not be needed when actors change positions. Tighter framings permit faster cutting.
A free-ranging camera:
1920s, prolonged following shots were developed and became prominent at the start of sound cinema. "thanks to lighter cameras and stabilizers like Steadicam, the shot pursuing one or two characters down corridors, through room after room, indoors and outdoors and back again, has become ubiquitous". Crane shots now serve as casual embellishment and now less marks a film's dramatic high point. Push-ins build tension and are used at a point of realization. Circling shots were a very common way to present people gathered around a dinner table and arching cameras showed lovers embracing. Sometimes the camera movement may serve as a point of view shot. A long shot is unlikely to be a static one.
Continuity has intensified because movies were increasing in durations and number of shots, so techniques were developed to save time, convey the meaning of the shots more clearly, and keep the attention of the audience.