With very-low-light capability, a few specific models of webcams are very popular to photograph the night sky by astronomers and astro photographers.
Mostly, these are manual-focus cameras and contain an old CCD array instead of comparatively newer CMOS array.
The term "webcam" (a clipped compound) may also be used in its original sense of a video camera connected to the Web continuously for an indefinite time, rather than for a particular session, generally supplying a view for anyone who visits its web page over the Internet.
Some of them, for example, those used as online traffic cameras, are expensive, rugged professional video cameras.
Webcams can be used to take video clips and still pictures.
Various software tools in wide use can be employed for this, such as Pic Master (for use with Windows operating systems), Photo Booth (Mac), or Cheese (with Unix systems).
Webcam features and performance can vary by program, computer operating system, and also by the computer's processor capabilities.
For example, the position of a single light source can be tracked and used to emulate a mouse pointer, a head-mounted light would enable hands-free computing and would greatly improve computer accessibility.Improved video quality has helped webcams encroach on traditional video conferencing systems.New features such as automatic lighting controls, real-time enhancements (retouching, wrinkle smoothing and vertical stretch), automatic face tracking and autofocus, assist users by providing substantial ease-of-use, further increasing the popularity of webcams.For a more complete list see Comparison of webcam software.Special software can use the video stream from a webcam to assist or enhance a user's control of applications and games.Unauthorized access of webcams can present significant privacy issues (see "Privacy" section below).In December 2011, Russia announced that 290,000 Webcams would be installed in 90,000 polling stations to monitor the Russian presidential election, 2012.This can be applied to games, providing additional control, improved interactivity and immersiveness.Free Track is a free webcam motion-tracking application for Microsoft Windows that can track a special head-mounted model in up to six degrees of freedom and output data to mouse, keyboard, joystick and Free Track-supported games.They have also become a source of security and privacy issues, as some built-in webcams can be remotely activated by spyware.The most popular use of webcams is the establishment of video links, permitting computers to act as videophones or videoconference stations.