CS-mount lens extender for full body CCTV cameras.

Is it possible to increase the focal length of an ordinary CS-mount CCTV camera lens?

A: Yes, you can double the focal length of a CS-mount lens using a 2x teleconverter. The teleconverter is fitted to the camera between the lens and camera body and once installed will multiply the focal length of the lens by 2.

A teleconverter will increase the F-stop value of a lens by one. Never add a teleconverter and then attempt to back focus the modified camera. It’s far simpler to back focus the camera and install the teleconverter afterward.

Pay attention to the focus, sharpness, contrast, chromatic aberrations and noise after you’ve added the teleconverter. Additional elements added to the optical equation always attenuate performance.

What you are doing with a teleconverter is exchanging image quality for reach – the increase in pixel density doesn’t cancel out the addition of aberrations in my experience. Field testing will tell you if the exchange is delivering operational benefits.