Monitor 8mm camera lens can be far
(1) to lens installation classification All camera lenses are threaded mouth, CCD camera lens installation has two industry standards, namely, C mount and CS mount. Both threads are the same, but the distance from the lens to the light-sensitive surface is different. C mount: The distance from the lens mounting datum to the focal point is 17.526mm. CS mounting seat: special C installation, then the front of the camera should be removed and then install the lens. The distance from the lens mounting datum to the focal point is 12.5mm. If you want to mount a C mount lens to a CS mount camera, you need to use the lens converter.
(2) to the camera lens specifications classification camera lens specifications should be based on the camera's CCD size, the two should be corresponding. When the camera's CCD target surface size of 1/2 inch, the lens should be selected 1/2 inch. When the CCD target size of the camera is 1/3 inch, the lens should be 1/3 inch. When the CCD target size of the camera is 1/4 inch, the lens should be 1/4 inch. If the lens size and camera CCD target surface size does not match, the observation angle will not meet the design requirements, or the screen outside the focus and other issues.
(3) to lens aperture classification lens with manual iris (auto iris) and auto iris (auto iris) points, with the camera to use, manual iris lens for the same brightness applications, auto iris lens due to brightness changes The aperture is also automatically adjusted, so the application of changes in brightness occasions. There are two types of auto iris: one is a video signal and power from the camera to the lens to control the lens on the aperture, called the video input type, the other is the use of direct voltage on the camera to directly control Aperture, called the DC input type. Auto iris lens on the ALC (automatic lens control) adjustment for setting the metering system, the entire screen can be the average brightness, you can also screen the brightest part (peak) to set the reference signal strength, the use of automatic aperture adjustment. In general, the ALC has been set at the factory and can be adjusted, but for images that contain a very high brightness target, the image of the bright object may cause a "white level clipping" So that all the screen becomes white, then you can adjust the ALC to transform the screen. In addition, the auto iris lens with aperture ring, turn the aperture ring, the luminous flux through the lens will change, the luminous flux that is the aperture, generally used F said, the value of the lens focal length and lens diameter ratio, that is: F = F (focal length) / D (the actual effective aperture of the lens), the smaller the F value, the larger the aperture. The use of auto iris lenses is ideal for the following applications where they have a wide dynamic range with an auto iris lens in situations such as direct sunlight. Requires a good focus in the entire field of view, with the auto iris lens has a greater depth than the fixed aperture lens. It is required that the auto iris lens should be used when the blurring caused by the optical signal is minimal on the light.
