There are a number of technical and artistic processes to get an image up on the big screen.
technical
fps
A film or video camera is used to capture or create the raw visual material from which a film will be constructed. Film normally runs at 24 frames per second (fps), video at 25 fps. This means that each second of film comprises 24 distinct still images, 25 on video.
Live Action & Animation
In 'live action' the continuous movement of actors (or cars, trains, animals etc) is captured in real time, as a series of 'frozen' images. In an animated film like The Sandman, each frame is photographed separately, with the figures moved slightly from one frame to the next, and it might take all day to produce one second of film.
Persistence of Vision
When seen on screen by the human eye, these 'still' images appear to show a continuous moving image. A perceptual phenomenon called persistence of vision, still only partially understood, is responsible for this.
Editing
From the footage generated by the camera, those few moments will be selected which best fit the director's and editor's purposes; and those selected moments will then be edited together to make the film. Some shots might also be altered, to take out unwanted elements in the image, to change colour balance, add special effects etc.
a 1940s film camera
artistic
staging the action
There are many decisions to be made relating to the camera when staging action:
- From which point/s will the action be filmed?
- How closely will we observe it, and from what angles?
- Will the camera move?
- Which lens will be required?
- How will it be lit?
The answers to these questions will depend partly on the overall conception of the film, of course, and each shot will be planned as part of that whole and as part of a sequence of shots. Each shot must be capable of following its predecessor and giving way to its successor in a seamless, invisible fashion.
Camera decisions, then, are made within a highly complex set of variables.
shot size
The scale of a shot, or the apparent closeness of the viewer to the subject in the screen image, is identified by terms like long shot, medium shot, close-up and so on. These terms identify particular points on a continuous spectrum of proximity - how 'tightly' or 'loosely' the screen's frame will enclose the subject.
There is no absolute definition for the many terms describing shot size. American, European and British schemes vary, as do individual interpretations.