Understanding Camera Mounting Interfaces

Hi, I am Katie, one of the Opto-Mechanical Engineers here at Edmund Optics. Today, I want to talk about the types of standard camera mounts in our catalog and what the differences are. Some of the common industrial camera mounts you will see in our imaging section are C-mount, S-mount, T-mount and F-mounts. Each of these mount types originated from the standardization of connecting imaging lenses to cameras. They are generally defined by their thread specifications, but some also have a standard flange focal distance, which is the effective distance from the mounting flange on the camera to the plane of the sensor. The flange distance is important because it defines the proper distance for the image to be focused on the sensor. The most common way to mount imaging lenses to industrial cameras is using a C-mount. C-mounts have 1-inch diameter threading with 32 threads per inch and a flange focus distance of 17.526mm. The less common but similar CS-mount has the same threading but a flange distance that is 5mm shorter. An easy way to remember this difference is by thinking of the CS-mount as the C short mount. This leads to the compatibility of C and CS-mount components. The ideal situation is to match a C-mount lens with a C-mount camera or a CS-mount lens with a CS camera. Furthermore, it is straight forward to combine a CS camera with a C lens if a 5mm adaptor is used. In fact, most CS cameras include this spacer for the use of standard C lenses. However, it is not possible to combine a C camera with a CS lens as the focus would never be close enough to the sensor plane to get a sharp image. In addition to C and CS mounts, we also carry products with S-mounts, T-mounts and F-mounts. S-mounts are commonly used for board level cameras and micro video lenses, such as those used in surveillance or webcams. They have an m12 by .5 threading which means a 12mm diameter and .5mm between threads. Our line of high-resolution micro video lenses will carry a standard S-mount. T-mount refers to an m42 by .75mm thread. Although the original T-mount standard refers to a 55mm flange focal distance, the T thread is used with a number of different flange distances, most commonly, the 6.56mm and 19.53mm, which are somewhat popular with the large sensor formats. This is not to be confused with the less common M42 by 1mm thread, which does not have a standard flange distance. F-mounts are unique in that they are not threaded. They are bayonet style where there is a turn and lock type mechanism to hold them in place as you see in this product. Developed originally for Nikon SLR, single lens reflex cameras, F-mounts have a flange distance of 46.5mm, and are common among large area scan sensors, line scan cameras and large format lenses. They are also commonly used in professional photography cameras. In general, adaptors can be used to connect lenses of a given thread to any camera with a flange to sensor distance shorter than the back focal length of the lens. Here is an example of a C-mount to a F-mount adaptor. Care must be taken to ensure that such an arrangement still allows full coverage of the sensor without vignetting, which is the mechanical clipping of the outer light brace. If you are unsure about the needs of your application, please contact our technical support. I hope this answers your questions about different types of mounts we offer, and which suit your needs. You can browse more of our technical application notes and videos to learn more key concepts and find answers to common questions on our website.