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A closed-circuit television camera is a type of surveillance camera that transmits video signals to a specific set of monitors or video recording devices, rather than broadcasting the video over public airwaves. The term "closed-circuit" indicates that the video feed is only accessible to a limited number of people or devices with authorized ...
Telecentric lens. Bi-telecentric lens with 208 mm diameter front element and a C-mount camera interface. A telecentric lens is a special optical lens (often an objective lens or a camera lens) that has its entrance or exit pupil, or both, at infinity. The size of images produced by a telecentric lens is insensitive to either the distance ...
C-mount lenses provide a male thread, which mates with a female thread on the camera. The thread is nominally 1 inch (25.4 mm) in diameter, with 32 threads per inch (0.794 mm pitch ), designated as "1-32 UN 2A" in the ANSI B1.1 standard for unified screw threads. The flange focal distance is 17.526 millimetres (0.6900 in) for a C mount.
Diagram illustrating the flange focal length of an SLR–type and a mirrorless–type camera. For an interchangeable lens camera, the flange focal distance (FFD) (also known as the flange-to-film distance, flange focal depth, flange back distance (FBD), flange focal length (FFL), back focus or register, depending on the usage and source) of a lens mount system is the distance from the mounting ...
Circle of confusion. In optics, a circle of confusion (CoC) is an optical spot caused by a cone of light rays from a lens not coming to a perfect focus when imaging a point source. It is also known as disk of confusion, circle of indistinctness, blur circle, or blur spot . In photography, the circle of confusion is used to determine the depth ...
Optical format is a hypothetical measurement approximately 50% larger than the true diagonal size of a solid-state photo sensor. The use of the optical format means that a lens used with a particular size sensor will have approximately the same angle of view as if it were to be used with an equivalent-sized video camera tube (an "old-fashioned ...
S-mount (CCTV lens) The S-mount is a standard lens mount used in various surveillance CCTV cameras and webcams. It uses a male metric M12 thread with 0.5 mm pitch on the lens and a corresponding female thread on the lens mount. S-mount lenses are often called "M12 lenses". Because the lens mounts are usually attached directly to the PCB of the ...
If a screen is 50 cm high and it is at a distance of 250 cm, then in picture heights, its distance is 5 H ( 250 50 ). Mathematically, this gives the distances shown in the following table: Distance in picture heights. Here the distance is 3.2 picture heights (H). This is the optimal viewing distance for HD 1080 video. Resolution.
An imaging system may have many individual components, including one or more lenses, and/or recording and display components. Each of these contributes (given suitable design, and adequate alignment) to the optical resolution of the system; the environment in which the imaging is done often is a further important factor.
Exposure value. Fast shutter speed (short exposure time) of a breaking wave. Slow shutter speed (long exposure time) of a breaking wave. In photography, exposure value ( EV) is a number that represents a combination of a camera 's shutter speed and f-number, such that all combinations that yield the same exposure have the same EV (for any fixed ...