Web camera sites
Some of them, for example, those used as online traffic cameras, are expensive, rugged professional video cameras.
As webcams evolved simultaneously with display technologies, USB interface speeds and broadband internet speeds, the resolution went up from gradually 320×240, to 640×480, and some even offering 1280×720 (aka 720p) or 1920×1080 (aka 1080p) resolution.
Most consumer webcams are capable of providing VGA-resolution video at a frame rate of 30 frames per second.
Many newer devices can produce video in multi-megapixel resolutions, and a few can run at high frame rates such as the Play Station Eye, which can produce 320×240 video at 120 frames per second.
As a camera system's depth of field is greater for small image formats and is greater for lenses with a large f-number (small aperture), the systems used in webcams have a sufficiently large depth of field that the use of a fixed-focus lens does not impact image sharpness to a great extent.
Most models use simple, focal-free optics (fixed focus, factory-set for the usual distance from the monitor to which it is fastened to the user) or manual focus.