FREQUENTLY ASKED QUESTIONS - M
Manual Iris Lens
Manual Iris Lens is a lens with a built-in method of manually adjusting lens aperture for the best video quality for a specific lighting condition. Iris control on such a lens is set by hand to a particular fixed aperture, allowing for the best possible (often better than auto-iris lenses) brightness and contrast for a specific camera angle/shot.
Maximum Recording Time
Maximum Recording Time indicates the longest continuous duration of time which could be recorded onto storage media using a VCR or DVR video recorder. Maximum recording time for ALL recorders will depend on the user setting for time lapse or real time recording and the amount of storage media capacity. Maximum recording time for DVR recorders is also dependent on resolution settings as well as hard disk drive capacity. Maximum recording time for analog VCR recorders will depend on the size cassette tape, usually VHS, which is installed in the recorder.
Multiplexer (mux) is a video switching device that accepts video input from multiple cameras and converts them to all display on one monitor and/or video recorder, similar to a quad video processor. However, a multiplexer is far more advanced than a simple quad processor. Video multiplexers use time division multiplexing, meaning that a full frame of video from each camera is recorded every few seconds. While multiplexed video does not achieve true real time display or recording (there is a slight drag to the images on playback), multiplexers do offer the capability to change between a view of several cameras and a solid close up view of only a single camera's view on playback of recorded video. When using multiple cameras, quads and multiplexers help to cut down on the amount of additional equipment needed for a dedicated surveillance system. However, DVR digital video recorders with multiple video inputs are quickly replacing quads and multiplexers. DVRs are now capable of doing what required a processor and VCR together to accomplish (plus a whole lot more).