1, the type of the lens (according to the classification of applications)
Wide angle lens: above 90 degrees angle, observation range near the image deformation.
Standard lens: visual angle of 30 degrees or so, the use of a wide range.
Telephoto lens: from the angle of 20 degrees, the focal length of up to tens or hundreds of mm mm.
Zoom: continuously variable focal length of the lens, the focal length can be changed from wide-angle to telephoto focal length, the longer the greater the imaging.
Pinhole lens: used for covert observation, often mounted on a ceiling or wall, etc..
2, the size of the object, distance and focal length of the relationship
Assuming the width and height of the object is W.H, the distance between the object and the lens is l, the focal length of the lens is f.
3, relative aperture
In order to control the flux through the lens size, back in the lens aperture are set. Effective aperture if aperture is D, because of light refraction, effective aperture mirror effective for D greater than D, D and f focal length is defined as the ratio of the relative aperture a, namely a=d/f, relative aperture lens decided by the camera illumination, reciprocal illumination and relative aperture of the lens said the size of the lens aperture. The smaller the F is, the larger the aperture, the flux reached CCD chip is bigger. So in the same case of focal length f, the smaller the F value, the better the lens.
4, lens focal length
1 fixed focal length: focal length fixed, can be divided into two kinds of aperture and no aperture.
Aperture: the size of the lens aperture can be adjusted. According to the changes in the environment, the size of the aperture should be adjusted accordingly. Aperture size can be adjusted manually or automatically, manual adjustment of the aperture, known as the manual aperture. Lens comes with a miniature motor automatically adjust the aperture, known as the automatic aperture.
No aperture: constant aperture, the light is fixed. Mainly used for light source constant or camera with electronic shutter.
2) zoom: the focal length can be adjusted according to the need to enlarge or reduce the image of the object. Commonly used zoom lens is six times, ten for sale.
Three variable and two variable lenses
Three variable lens: adjustable focal length, focus adjustment, adjustable aperture.
Two variable lens: adjustable focus, adjustable focus, automatic aperture.
5, first with the lens principle
In order to obtain the expected effect of the camera, in the matching lens, we should pay more attention to the six basic elements:
A) the size of the object being photographed
B) the details of the object to be taken
D) focal length
CCD) e camera target size
F) the resolution of the lens and the camera system
6, operating procedures:
Remove the lens tip device, connect the lens.
If you use the CS lens, to C ring (5mm), then locked CS lens device.
C type lens can be directly installed and used.
Connect video output (BNC) to monitor or other device.
Plug in DC12V power /ac220v* check whether the LED light.
When the image is blurred, adjust the focal length of the lens.