In industrial vision inspection, the role of the lens is to image the target on the photosensitivity of the image sensor, and plays an important role in the quality of visual image imaging. It is an important part of the composition of the machine vision system, and the commonly used lenses are mainly telecentric lenses, fixed-focus FA lenses, zoom lenses and so on. These lenses have their unique applications and advantages in industrial vision inspection, but there are some differences between them.

Telecentric lens is a special kind of industrial lens, which adopts telecentric optical design, which can ensure that within a certain range of object distance, the size of the field of view of the object side is proportional to the object distance, and has nothing to do with the focal length of the lens. Therefore, in industrial vision inspection, telecentric lenses can accurately measure the size and shape of objects and are suitable for high-precision measurement and identification.

Variable-magnification lens is a kind of industrial lens whose magnification can be continuously adjustable within a certain range, which is characterised by high resolution and high contrast, and the focal length of the lens can be continuously changed. In the case of not changing the object distance, the lens magnification changes, that is, the shooter can not have to adjust the times to shoot the distance of the scene, you can change the shooting field of view and the size of the image. Zoom lens using infinity optical system, the entire field of view can be obtained excellent image quality.

Fixed-focus lens is a focal length can not be adjusted industrial lens, but focus fast, stable image quality, suitable for detecting the working distance is fixed as well as the detection area is the same plane of the scene. Fixed focus lenses may not be able to meet complex or highly variable inspection needs in some cases.

The difference between telecentric lenses and zoom lenses and fixed focus FA lenses and other non-telecentric lenses lies in their respective characteristics and scope of application. Choosing the right type of lens needs to be determined based on specific inspection needs and application scenarios.