Scenes in films can last from mere seconds to minutes on end, with the length of each sequence establishing pace for how the film should progress on during and from this point. The speed of editing can create both atmosphere and mood to the characters in the film and the audience.
In order to create anxiety and suspense to the audience,the use of fast editing and scene changes in quick succession to each other are the most effective in presenting theses emotions.
On the other hand, in order to portray calm or romance, scenes tend to last longer and change less frequently to exaggerate these emotions.
Film trailers commonly use fast editing to pack in as much information in the film without giving away the entire storyline or lasting to long.
In the openings of films, so as the story and main characters are being introduced, the editing has to be slow and flow well in order to present to the audience where and who they are concerned with. As the film progresses, scenes may vary and even cross cut to show one or more situations in detail.
Cross Cutting
The idea of cross cutting is to present two or more sequences to the audience at once that have some relation to each other. This means something will be happening at the same time as something else but in a different location. An example of this is 'The Race Home' scene in Ferris Buellers Day Off, directed by John Hughes. As Jenie floors it home, we see Ferris running through multiple different gardens, back allies and roads to get home before her. These scenes, when cross cut together, emphasise the rush and competitive relationship between the siblings. This is also emphasised by the fast editing, creating a quick pace and making the audience feel the desperation that the siblings have to catch each other out.
Engaging the viewer
The use of camera angles, the speed of scene change, actions themselves and rapid storyline are all concepts of pace used to engage the viewer. An example of this is the Gunfight scene from The Good, The bad and The Ugly, directed by Sergio Leone, in which three cowboys have a shoot out to win whatever hidden treasures there are in a graveyard. The camera angles change from wide shots to close ups as the tension rises between the men. Once the first shot has been fired, the pace quickens, with scenes changing rapidly and camera angles varying.