The series of extension tubes automatically connect the lens and camera mechanism together to utilize the camera's functions fully for ease of use. | | With the exception of Extension tube 8, which cannot be connected directly to the 200-series cameras, they also feature a data bus coupling to transfer data from the lens to the exposure metering system of the camera. | | Extension tube 8 (3040649) Extension tube 16E (3040654) Extension tube 32E (3040655) Extension tube 56E (3040656) |