Increase the function of your digital SLR camera by adding a T-mount adapter. The Opteka T-Mount (T2) allows you to mount a T-Mount lens to your Canon EOS camera body. Besides for making financial sense, this allows you to use your favorite lens across different camera platforms. It also allows you to attach your SLR-type camera to a telescope. The lens adapter is designed to fit securely to the lens, yet can still be removed easily when not needed. Although the lens will fit physically, autofocus, automatic diaphragm (AE metering), and other functions dependent on communication between camera body and lens will be disrupted by the lens adapter. You will need to focus manually, and to set exposures manually or meter in aperture priority (stop-down) mode. If the lens does not have a manual aperture collar, the aperture will be stopped down to its smallest f/stop. Focusing to infinity is retained.