With the rapid advancement of machine vision technology, selecting core components such as industrial cameras, machine vision lighting, and industrial lenses is essential when developing a machine vision system. Today, we will begin by introducing in detail the classification of industrial lenses. Industrial lenses come in various types and specifications; below is a categorization based on interface and application.

Classified by industrial lens interface

1.CCTV（C-MOUNT）

Also known as C-type industrial camera lens, it is a widely used industrial lens in machine vision systems at present. It has the advantages of light weight, small size, low price and a wide variety of types.

One of the variations of the C installation interface is called CS-mount. The only difference between CS-mount and C-MOUNT is that the distance from the positioning surface of the industrial lens to the light-sensitive surface of the image sensor is different. C-MOUNT is 17.5mm, while CS-mount is 12.5mm, with a difference of 5mm. All the industrial lens products on the market, such as the ZML series of small zoom and zooming industrial lenses, all adopt the standard C interface.

The CS-MOUNT interface was designed for the new CCD. As the CCD technology developed, its integration level increased, and the light-sensitive arrays with the same resolution became smaller. Therefore, the CS-MOUNT is more suitable for industrial cameras with smaller effective light-sensitive sensor sizes.

Industrial cameras with CS interface can be connected to both C and CS type interfaces. However, when installing industrial lenses on C interfaces, an adapter ring needs to be added. Industrial cameras with C interface can only be connected to industrial lenses installed on C interfaces and cannot be connected to those installed on CS interfaces. Otherwise, not only will good focus not be achieved, but the CCD target surface may also be damaged.

2.35mm industrial camera lens

This type of industrial lens is the 35mm industrial camera lens used in daily life. From the perspective of cost-effectiveness, it is an excellent industrial lens. Many industrial cameras and linear array scanning CCDs require the use of this type of industrial lens.

One drawback of the 35mm industrial lens is its bayonet-style fixation method. When used in an environment with vibrations, this fixation method causes the industrial lens to move. Therefore, in a machine vision system, the 35mm camera industrial lens is not a good choice.

3.Classified by the equivalent focal length of industrial lenses

3-1.Wide-angle industrial lens

An industrial lens with an equivalent focal length less than the standard focal length (50mm). Its features include a short working distance (WD), large depth of field, wide field of view, and usually barrel-shaped distortion.

3-2.Telephoto industrial lens

When the equivalent focal length exceeds 200mm, the working distance is long, the magnification is large, and the distortion usually manifests as barrel distortion.

3-3.Medium focal length industrial lens

The industrial lenses commonly used in machine vision systems have a focal length of around 50mm, which falls between the wide-angle industrial lenses and the telephoto industrial lenses. Generally speaking, they have better distortion correction.

3-4.Telephoto industrial lens

In machine vision systems, the size of objects is often very important. However, in general industrial lenses, objects that are far away from the lens result in smaller images, while objects of the same size that are close by result in larger images. As a result, measurement errors occur. The telecentric industrial lens is designed to eliminate this error, so that objects of the same size but at different distances can obtain images of the same size on the imaging surface. Telecentric lenses are divided into single telecentric lenses and dual telecentric lenses.

3-5.Macro industrial lens
An industrial lens designed for capturing smaller objects, it features a very high industrial lens magnification ratio.

4.Classified by the functions of industrial lenses

4-1.Variable focal length industrial lens

It is in contrast to the fixed-focus industrial lenses. By moving the lenses within the industrial lens, the focal length of the industrial lens can vary within a certain range. Thus, without the need to replace the industrial lens, the CCD industrial camera can obtain both panoramic images and detailed local images. The zoom industrial lenses typically come in various ranges such as 6x, 8x, 10x, 12x, 16x, 20x, and 50x.

4-2.Variable aperture industrial lens

In industrial lenses, a variable aperture capable of controlling the amount of light input is installed, allowing the relative aperture F of the industrial lens to change continuously, so as to adapt to the correct exposure of objects of different brightness. When adjusting the size of the aperture as mentioned earlier, it can affect the length of the depth of field. Therefore, in order to achieve the effect of a large depth of field, under the condition of permitted lighting, the intensity of the lighting should be increased as much as possible and the aperture should be reduced to obtain a larger depth of field.

According to their functions, they can be further classified into automatic focus industrial lenses, automatic aperture industrial lenses, and so on.