Contax 645 - Cable Switch
The Contax LA-50 Cable Switch can be used for close-up or telephoto photography when using a tripod or any other time you wish to release the shutter remotely.
Pressing the cable switch offers the same functionality as pressing the shutter release on the camera body.
Auto focus is enabled by pressing the release half-way down. Additional features include a lock for Bulb exposures or for continuous shooting.