For the most customers who using the Industrial camera selection process are also need to choose the lens when choosing the camera .This selection process is the industrial camera lens gradually explicit process parameters.For imaging devices, the industrial camera usually with light source, camera constitute a complete image acquisition system together, so the choice of industrial camera lens are restricted by the system requirements ,your image and distance vision etc.So you can analyze and consider the several aspects as follow when choosing and purchasing .

First:the wavelength is zoom or not ?
It is much easier to determine whether the Industrial camera work wavelength need to zoom or not ,If it is the necessary to change the magnification in the process of imaging applications, you can adopt a zoom lens, otherwise the fixed focus lens will be OK .As regard the work wavelength of industrial camera , visible waveband is the common and there are also other applications of waveband.Do you need another filter measures?Monochromatic or polychromatic light? Can it avoid the influence of stray light effectively ?Considering this few problem clearly and make sure the lens of work wavelength again after the comprehensive measure.

Second:the special requirements is the priority to considered
You should more clear it may have some special requirements when combining with the actual application .such us whether is a measurement functions , whether it is the necessary to use the telecentric lens, imaging depth of field is so big or not ,etc .The depth of field is often ignored, but any imaging system must be considered it .

Thirdly:the working distance &focal length
Working distance and focal length often combine to considered.In general,you can adopt this idea: Firstly you should clear the resolution of the system ,it can see magnification when Combining with the CCD pixel size and it can know about the image of distance when combining spatial structure constraint, then you can estimate the focal length of the camera lens further.So the focal length of Industrial camera lens is related to the industrial working distance, system resolution and the CCD pixel size .

Fourth:Pixel Size and Image Quality
Choosing the pixel size of industrial camera lens should be compatible with digital sensor surface according to the principle of "big compatible with small ".Digital sensor surface could not bigger than the labeled lens dimensions , or the edge of the field of image quality will be affect .As image requirements mainly focus on MTF and distortion, especially we should pay attention to distortion in measuring application.

Fifth:Aperture and Interfaces
The aperture of the camera lens mainly influence brightness of the pixel size .But in the machine vision ,the brightness of the final image is decided by many factors: camera aperture, gain, integral time, light, etc.So it has more link for adjustments in order to obtain the necessary image brightness.Industrial camera lens interface is connected the camera interface, both of them must be match and or not you should consider to transfer.

Sixth:Cost and Technical Maturity
You can consider to the cost and technical maturity and make the meritocratic selection, If it can meet the solutions requirements after considering the above factors.

Recently, we received a solution from one of our customers ,which is test the steel plate crack,and our solution camera is :1/2 CCD with C-Mount, pixel size: 4.65 mu m * 4.65 mu m,working distance: 200 mm,accuracy requirements :0.05 mm.
We carried out the analysis of the operation:
1. It is necessary to choose the smaller lens distortion through comparing the precision when choosing the camera and lens for   used for industrial inspection with the measuring function .
2. Imaging magnification and focal length Imaging of magnification:M=4.65/（0.05x1000）=0.093 Focal length:f’=L*M/（M+1）=200*0.093/1.093=17mm Object distance requirement is greater than 200 mm, so the lens of the focal length should be greater than the 17 mm.
3.The lens pixel size should not be less than the CCD size, that is at least 1/2 inch
4.The lens should be C-mount ,which can be used with the camera.
We can preliminarily concluded that the lens according to the above analysis and calculation:Focal length is more than 17 mm with fixed focus and C -MOUNT ,which can use with 1/2 inch CCD and small image distortion. You can choose the lens according to qualification if most of them can meet these requirements.