Video Photography and Editing

Author: Gao Xiaohong / et al.
Editor-in-Chief: Ye Guigang
Publisher:
Publish Date: 2003-08-01
Features:
Segment: Chapter Television Images
If television cinematography is a technical trade, then its "product" is the television image; if it is an art form, there is no doubt that its "work" is still the television image. In short, the television cinematographer engages in the work of recording images (including sound) based on materials such as electricity, cameras, and magnetic tapes. The image data "recorded" by the cinematographer on the tape is also known as "image material," which is the "raw material" for all television programs. As the original creator and recorder of television images, the cinematographer's work is closely tied to the camera, which is why some jokingly call them "camera bearers." Let us begin with the camera and television images and dive into the study of television cinematography, which holds a bright future.
Section Television Cameras and Television Images
Modern electronic recording and playback equipment are an indispensable material foundation for television cinematography. The camera is the tool and weapon of every cinematographer. "A workman must have his tools if he wishes to do his work well," as the saying goes. It is not only the most important and basic equipment in the television program production process but also the prerequisite and key to determining the technical quality of the program. The camera utilizes the principle of photoelectric conversion of the camera equipment and the electronic scanning method in television technology to convert the light signals captured by the lens into corresponding electrical signals. These electrical signals are then encoded through a series of processes and combined into standard color video signals. When the color video signals obtained by the camera are sent to the video input terminal of the videotape recorder, these images are recorded on the videotape in the form of magnetic signals. If these color video signals are transmitted directly to a television monitor via a video cable or broadcast through a color television transmission system and received by televisions within a certain distance, then we can see the images captured by the camera lens—the television image.
I. Composition and Classification of Cameras
The technical development of cameras has gone through several stages, including vacuum tubes, transistor and integrated circuits, and microelectronic solid-state imaging devices. However, regardless of the model or equipment, the basic structure and principles of a television camera remain the same. Typically, a camera consists of an optical system, a photoelectric conversion system, an image signal processing system, and an automatic control system. The optical system of the camera is composed of zoom lenses, color temperature filters, and red-green-blue (RGB) splitting systems, which can obtain red (R), green (G), and blue (B) primary light images imaged on their respective corresponding camera targets. The role of the camera's photoelectric conversion system is to convert the light images imaged on the target into electrical signals. These signals are then amplified, corrected, and processed by the image signal processing system, while simultaneously completing the signal encoding work, ultimately forming a color full television signal output. Before and during shooting, many adjustments are required. To facilitate operation and flexibility, most cameras are equipped with automatic or motorized control devices, known as the automatic control system, such as automatic white balance adjustment, automatic black balance adjustment, automatic iris, motorized zoom, automatic gain control, and automatic focus. In addition to the above major working systems, cameras also have some auxiliary components, mainly including videotape recorders, color bar signal generators, and AC/DC power supplies. Due to the variety of cameras and the diversity of manufacturers, classification methods also differ. Sometimes, cameras of the same category may have many different names. With the continuous advancement of technology and the constant updating of components, the types and uses of cameras have become increasingly diverse. Below is a brief introduction to the main classification of cameras.