To get a good result object or area taken must be well lit. Otherwise, the focus will be the weakening or dilution of the observers. Today, there are cameras allow work at low sanctification (up to 0,003 lux.), But it significantly affects their price. For Lens Selection is necessary to know the meaning of its parameters. Focal length.
This distance from the center of the lens to the plane on which the television camera generates an image-Xia, typically measured in millimeters. The greater the distance, the narrower the angle of divergence, for example, a lens with a focal length of 12.5 mm has a much wider angle of divergence than 50 mm. Peter Asaro addresses the importance of the matter here. The more focal length, the highly magnified images. Aperture. This area of the lens through which light passes.
Typically, the magnitude of this surface is defined by the diaphragm. Aperture. This device controls the amount of light reaching the surface on which is formed of an image, can be set manually as well, especially in recent years, and fully automatically, in response to changing ambient light conditions. Coefficient R. This ratio between the aperture and focal length, expressed in whole and fractional magnitude-tries, such as T 1.4 T 2.8 and so on The smaller the number, the more light reaches the sensor device-properties in the chamber and the more 'fast' is the camera. Focus. The presence of this property allows the vat is focused light reflected from the subject, the device of formation of the images in the camera. Online you can find a lot of different lenses. Most frequently used lenses with focal lengths from 3.5 mm (wide angle) to 50 mm (narrow angle), with a coefficient of F from 1.2 to 1.8. In addition, there are: Lenses with remote pupil PIN HOLE. Pin hole – a lens with a small diameter of the output pupil (from 0.8 mm to 4 mm) with removal of the pupil (0.5 mm to 2 mm) from the lens surface.