C Mount Telecentric Lens | Beginner’s Guide to Their Application & More
As we are all familiar with the fact that the use of Machine Vision technologies has instantly increased in various C mount telecentric lens applications. Furthermore, its popularity has risen to the point that it is found in almost every other domain or industry. The enhancement of the camera, software elements, and illuminations has also made it a lot easier to capture clean and clear images. Likewise, these images are much better than those detected with lasers and other conventional techniques.
As we know, high-quality optics can achieve high-performance outcomes. You can make a significant investment in high-quality telecentric lenses if you need specific magnification for a particular application. So, what are telecentric lenses? How does this C mount CCTV lens perform? How can you pick the right lens for your use?
Nevertheless, these queries have hampered many individuals from using these lenses. Additionally, in this comprehensive blog, we will cover everything that every person should know about the telecentric lens and its usage. Take your time to read this blog if you want to gain knowledge about telecentric lenses.
What is a C Mount Telecentric Lens?
C mount telecentric lens is a special type of lens typically used to increase image-capturing performance. Also, they can help to lower capture and distortion dimensions appropriately. In telecentric lenses, the stop gap is precisely placed on the focal plane. It gives the outcome in the incoming rays concentrated on the entrance pupil. However, this entrance pupil emerges to be virtually positioned at infinity. These C-mount lenses are often used for long-range cameras to capture clean images. Similarly, telecentric lenses can provide a sharper field of view for a clear picture.
Moreover, before we look forward to this informative blog, you must comprehend the basic theory behind image capturing and how the C mount CCTV lens captures exceptional shots. Therefore, telecentric lenses are ideal for multiple machine vision applications, where the capturing distance between the target and the camera is long. Telecentric lenses are also appropriate for applications that need detailed measurements or precise alignment. Furthermore, the lenses have a remarkable design that keeps the object size constant, regardless of the distance between the object and the lens.
What are the Different Types of C-Mount Telecentric Lenses?
Telecentric lenses are not limited to one type. Likewise, it comes in three different broad types: Object-space Telecentric Lens, Image-Space Telecentric Lens, and Bi-Telecentric Lens. Let’s discuss them one by one to get a clear understanding.
1. Object Space Telecentric Lens
Object space telecentric lens mounts the gap diaphragm on the area focal plane of the picture. Therefore, when the lens’s aperture iris is on the camera, the length of the border of the image will fluctuate. Nevertheless, that does not mean that the precise height of the image will change. In short, this specific type of telecentric lens can capture the picture while maintaining the measured object size intact. Hence, the object distance S-mount lens or telecentric lens is appropriate for industrial applications.
2. Image Space Telecentric Lens
The space between the image sensor or film and the lens does not matter in image-distance telecentric lenses. Moreover, these lenses can still formulate images of the same size. Likewise, the exit pupil of the camera focuses on different spaces and forms an image without impacting the size.
3. Bi-Telecentric Lens
The bi-telecentric lens is a remarkable type that merges the key elements of both the object space and image-space telcentric lenses. Similarly, these lenses are stable and precise. Also, they have low distortion, a considerable depth of field, and high magnification. Bi-telecentric lenses are used for both machine vision and industrial vision image processing.
Technical Configuration of Telecentric Lens
| Parameter | Description | Typical Value / Range |
|---|---|---|
| Mount Type | Lens mount interface for a camera | C-mount (1″–32 UN 2A thread, flange focal distance 17.526 mm) |
| Optical Type | Lens design type | Telecentric (object-side or bi-telecentric) |
| Magnification (M) | Ratio of image size to object size | 0.1× to 4× (varies by model) |
| Working Distance (WD) | Distance from the front lens to the object | 50 mm – 300 mm (model-dependent) |
| Field of View (FOV) | Viewable area at given magnification | Depends on sensor size and magnification |
| Depth of Field (DOF) | Range of focus at a fixed position | Typically ±0.1 mm to ±2 mm |
| Telecentricity Error | Deviation of chief rays from parallelism | ≤0.1° (object-side telecentric) |
| Distortion | Image geometry deviation | <0.1% (often near zero) |
| Aperture (f/#) | Effective F-number (controls brightness/resolution) | f/4 – f/16 (fixed or adjustable) |
| Resolution | Maximum resolvable detail | Up to 5 µm / pixel (depends on sensor) |
| Sensor Compatibility | Image sensor format | 1/2″, 2/3″, 1″, 4/3″, APS-C, etc. |
| Illumination Type | Compatibility with the lighting setup | Coaxial or external illumination |
| Object Telecentricity | Ensures constant magnification regardless of object distance | Yes |
| Back Focal Length (BFL) | Distance from lens rear to image plane | Typically 17.526 mm for C-mount |
| Mechanical Length | Physical length of lens assembly | 70 mm – 200 mm (depending on model) |
| Weight | Total lens weight | 200 g – 800 g |
| Material | Housing and optical material | Aluminum body, optical glass elements |
| Mounting Features | Mechanical support | M4 or M6 mounting holes, clamping ring |
How Do Telecentric Lenses Work?
Telecentric lenses diminish the edge angle of the light rays and the image sensor. With this, there is little to no distortion, enhancing the quality of the captured image. In standard optics, the light rays typically curve at different angles when they exit the lens. Besides, a C mount CCTV lens works differently, keeping all light rays parallel to each other after leaving the lens. You can quickly notice the significant difference by comparing the pictures captured by telecentric and ordinary lenses. Furthermore, you will see that images captured by telecentric lenses have extensive detail and precision. Also, the remarkable parallel position of light rays allows lenses to concentrate on distant subjects.
Now, you might wonder how telecentric lenses capture and work accurately with images. Well, the secret lies in the formation of C-mount telecentric lenses. In C-mount telecentric lenses, two camera lenses are put together with multiple focal lengths. The first lens captures light from the subject, and after this process, it directs the light to the second lens. Lastly, the second S-mount lens projects the light to the backend of the device, that is, the diaphragm. Nonetheless, this device regulates the right amount of light entering the sensor, ensuring only light rays parallel to each other can pass through its surface.
Pros and Cons of C Mount Telecentric Lens
| Pros | Cons |
|---|---|
| Minimized Perspective Error | Higher Cost |
| High Measurement Accuracy | Limited Field of View (FOV) |
| Uniform Illumination and Focus | Bulky Design |
| Compact and Standardized Mount | Reduced Light Throughput |
| Stable Optical Performance | Fixed Magnification |
Applications of Telecentric Lenses in Different Industries
Inspection and quality control are two major processes followed in the manufacturing process. Nowadays, multiple industries are depending on advanced technologies to perform these operations. Additionally, the machine vision industry is not an exception to it. Furthermore, some of the significant applications of C mount telecentric lens in the machine vision industry are mentioned below:
1. Textile Industry
2. Manufacturing of Lithium-ion Batteries
3. Automotive Industry
4. Medical Devices and Materials Industry
5. Semiconductor Manufacturing Industry
6. Mobile Components Manufacturing Domain
7. 3C Electronics Production Sectors
8. Solar Power and Printing Industry
It’s Time to Wrap Things Up!
The telecentric lens has become an imperative part of machine vision systems. That is because they have an extensive working distance and massive magnification. Standard lenses often raise common problems, impacting the image processing experience. Furthermore, it includes poor image resolution, perspective errors, image distortion, and the anticipation of an object’s edge position.
C mount CCTV lens or telecentric lenses can decrease or even prevent all such problems. They can achieve high precision and accuracy in imaging systems. Superior CCTV manufactures a wide range of telcentric lenses in different parameters. You can use our professional telecentric lens customization service if you have specific needs and preferences. So, do not wait any further. Get your telecentric lenses today!