What is the C-mount?

Understanding the C-mount in Optical Systems

The C-mount is a standardized type of lens mount prominently utilized in photography and video applications, including CCTV, machine vision, and scientific microscopy. Developed by the RCA Corporation, this mounting interface is especially recognized for its simplicity and versatility in attaching lenses to cameras.

Specifications

C-mount specifications include a 1-inch diameter thread with a 32 threads per inch (TPI) pitch. One of the critical aspects of the C-mount is its 17.526mm flange focal distance, which is the distance from the mounting flange (the metal ring on the camera and the back of the lens) to the image plane.

Advantages and Applications

C-mounts offer several advantages, such as compatibility with a wide range of cameras and lenses, and the ease of use due to its straightforward mechanical connection. This compatibility fosters a vast ecosystem of accessories, including extension tubes and adapters, permitting their application in a diversified array of fields beyond traditional photography, such as industrial inspection, robotics, and scientific research.

CS-mount Variation

Alongside the original C-mount, the CS-mount emerged as a variation, possessing a shorter flange focal distance of 12.526mm. Though the two are physically similar, they are not directly interchangeable without an adapter. Cameras and lenses designed for CS-mount cannot be used with C-mount fittings without an extension adapter to compensate for the differences in flange focal distance.

Conclusion

In conclusion, the C-mount's enduring popularity and relevance in optical engineering can be attributed to its flexibility, adaptability, and the broad support of the accessory ecosystem. Its standardized design ensures it remains a staple in both traditional and innovative imaging applications.