Q.What is 1/3, 1/4 Image Sensor or Image Device or Pick-up Element?
A.Common formats of Image Sensors/Device or Pick-up Element are 1/4”, 1/3” . The size of the sensor directly affects the field of view obtained. When using the same size lens on different format sensors, different viewing areas are obtained. e.g: using a 6mm lens on a 1/3” sensor will give you a 37º field of view. Using the same lens on a 1/2” sensor will increase the field of view to 56º and 74º on a 2/3” sensor.
Q.What is Aperture F-Number?
A.In CCTV optics, the aperture is the diameter of the lens that controls the amount of light reaching the image sensor. It is shown by an f-number. Larger aperture lenses have smaller f-numbers. For instance, a lens with an f-number of 1.2 will allow more light to reach the sensor than a lens with an f-number of 2.0 thus producing a brighter image. The higher the f number the less light is permitted to pass into the camera.
Q.What is TVL ?
A.TVL refers to Resolution of a CCTV Camera, how detailed a picture the camera can see. The measurement to look for is horizontal TV lines (TVL). A normal CCTV picture is around 380 to 420 TVL, with high resolution getting up to 480 or 580.
Q.What is SN Signal to Noise ratio ?
A.S/N Ratio indicates how much Signal or actual picture information, the camera transmits, as opposed to Noise which comes across as static. A s/n ratio of 40dbindicates that the signal is 100 times the noise, which results in an acceptable picture withsome fine grain or snow. 30db results in a poor picture, and 60db produces an excellentpicture with no static visible.
Q.What is LUX?
A.Sensitivity to light is measured in lux. A sensitivity of 0.2lux means the camera can see fairlywell by the light of a 40W fluorescent bulb light
Q.What is AGC Automatic Gain Control?
A.Many cameras come with an AGC circuit. This circuit examines the brightness level of the video signal to keep it at a consistent level. For example, if the video signal is dark, it will attempt to increase the gain to bring the brightness up to a normal level.
Q.What is Auto-Iris Lens or Control?
A.An auto iris lens is a lens that automatically adjusts to only allow a specific amount of light to reach the image sensor. When there is low light, the iris will open to let more light in. When there is too much light, the iris will close to reduce the amount of light let in. Auto iris lenses are primarily used in applications where light levels vary and it would be impracticable to manually adjust the lens. Automatic iris lenses are generally more efficient than the electronic shutter since they actually control the amount of light reaching the sensor as opposed to simply adjusting shutter speed.
Q.What is BLC Back Light Compensation?
A.Many C/CS Mount CCTV Cameras include a BLC circuit. This circuit is used to help correct an image with more light behind the subject being viewed. Without backlight compensation, the subject appears dark with little detail. Using the backlight compensation will reduce the brightness of the light to allow the subject to appear brighter and bring out the details.
Q.What is C/CS Mount Lenses or Camera?
A.Advantage of a C-Mount Camera is that the lens can be changed as per your requirement. If you want to see further than 40 or 60 ft. then you'll need a c-mount camera with a C-Mount lenses which are available from 3.6mm to 50mm. A 3.6mm lens provides facial detail and a 70 degree angle of view focused up to about 35 ft. A higher mile meter lens will provide Higher distance, but narrows the field of view. A 16mm lens would provide about only 15 to 20 degree angle of view at a focus distance of about 35 ft (or a 70 degree angle of view at about 140 feet). In general, 8mm lens is like a 4mm lens zoomed in 2 times. Similarly, a 16mm lens is like the 4mm lens zoomed in 4 times.
Tthe best option is to use a C/CS Mount varifocal lens. This will allow you to vary the focus from 3.6 to 60mm. So when you install the camera you can fine tune the focal distance and angle of view. Use a varifocal lens in outside (or inside) a large commercial building where you need more distance than 35 ft. the varifocal lens will allow you to adjust the focal distance to your preference.
Q.What is IR Infrared (Night Vision) Camera?
A.The area below the visible spectrum.where a Human Naked Eye can't See, CCTV Camera with IR LED's Can Capture & Show Picture even in Pitch Dark,
Q.What is Super HAD?
A.Super HAD CCD is a version of Sony’s high performance with improved sensitivity of more efficient microlenses. The Super HAD optimizes the shape of the on-chip lenses in order to minimize the ineffective area between the lenses on each pixel thereby minimizing lost light and improving the overall sensitivity per pixel.
Q.What is White Balance?
A.Color cameras only. Different lighting sources provide different color temperatures. The white balance helps correct these differences by adjusting the color processing to bring the color temperature to a fixed level. Without this balancing feature, due to the CCD’s poor adaptability, some colors would appear different (green instead of white in sunlight).