Video camera in the context of "Silicon Imaging"

Video feedback is the process that starts and continues when a video camera is pointed at its own playback video monitor. The loop delay from camera to display back to camera is at least one video frame time, due to the input and output scanning processes; it can be more if there is more processing in the loop.

A camera lens, photographic lens or photographic objective is an optical lens or assembly of lenses (compound lens) used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capable of storing an image chemically or electronically.

There is no major difference in principle between a lens used for a still camera, a video camera, a telescope, a microscope, or other apparatus, but the details of design and construction are different. A lens might be permanently fixed to a camera, or it might be interchangeable with lenses of different focal lengths, apertures, and other properties.

Digital imaging or digital image acquisition is the creation of a digital representation of the visual characteristics of an object, such as a physical scene or the interior structure of an object. The term is often assumed to imply or include the processing, compression, storage, printing and display of such images. A key advantage of a digital image, versus an analog image such as a film photograph, is the ability to digitally propagate copies of the original subject indefinitely without any loss of image quality.

Digital imaging can be classified by the type of electromagnetic radiation or other waves whose variable attenuation, as they pass through or reflect off objects, conveys the information that constitutes the image. In all classes of digital imaging, the information is converted by image sensors into digital signals that are processed by a computer and made output as a visible-light image. For example, the medium of visible light allows digital photography (including digital videography) with various kinds of digital cameras (including digital video cameras). X-rays allow digital X-ray imaging (digital radiography, fluoroscopy, and CT), and gamma rays allow digital gamma ray imaging (digital scintigraphy, SPECT, and PET). Sound allows ultrasonography (such as medical ultrasonography) and sonar, and radio waves allow radar. Digital imaging lends itself well to image analysis by software, as well as to image editing (including image manipulation).

A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in video telephony, live streaming and social media, and security. Webcams can be built-in computer hardware, like a laptop, or peripheral devices, and are commonly connected to a device using USB or wireless protocol.

Webcams have been used on the Internet as early as 1993, and the first widespread commercial one became available in 1994. Early webcam usage on the Internet was primarily limited to stationary shots streamed to web sites. In the late 1990s and early 2000s, instant messaging clients added support for webcams, increasing their popularity in video conferencing. Computer manufacturers later started integrating webcams into laptop hardware. In 2020, the COVID-19 pandemic caused a shortage of webcams due to the increased number of people working from home and children attending school remotely.

Ghost hunting is the process of investigating locations that are purportedly haunted by ghosts. The practice has been heavily criticized for its dismissal of the scientific method. No scientific study has confirmed the existence of ghosts. Ghost hunting is considered a pseudoscience by the vast majority of educators, academics, science writers and skeptics. Science historian Brian Regal described ghost hunting as "an unorganized exercise in futility".

Typically, a ghost-hunting team will attempt to collect "evidence" supporting the existence of paranormal activity. Ghost hunters also refer to themselves as paranormal investigators. Ghost hunters use a variety of electronic devices, including EMF meters, digital thermometers, both handheld and static digital video cameras, including thermographic and night vision cameras, night vision goggles, and digital audio recorders. Other more traditional techniques are also used, such as conducting interviews and researching the history of allegedly haunted sites. Dowsing and Ouija boards are other traditional techniques.

A camcorder is a self-contained portable electronic device with video and recording as its primary function. It is typically equipped with an articulating screen mounted on the left side, a belt to facilitate holding on the right side, hot-swappable battery facing towards the user, hot-swappable recording media, and an internally contained quiet optical zoom lens.

The earliest camcorders were tape-based, recording analog signals onto videotape cassettes. In the 2000s, digital recording became the norm, and additionally tape was replaced by storage media such as mini-HDD, MiniDVD, internal flash memory and SD cards.

In filmmaking and video production, footage is raw, unedited material as originally filmed by a movie camera or recorded by a digital video camera, which typically must be edited to create a motion picture, video clip, television show, or similar completed work.

Footage can also refer to sequences used in film and video editing, such as special effects and archive material (for special cases of this, see stock footage and B roll).

Signal modulation is the process of varying one or more properties of a periodic waveform in electronics and telecommunication for the purpose of transmitting information.

The process encodes information in form of the modulation or message signal onto a carrier signal to be transmitted. For example, the message signal might be an audio signal representing sound from a microphone, a video signal representing moving images from a video camera, or a digital signal representing a sequence of binary digits, a bitstream from a computer.