Lenses between different brands and different bayonets can be transferred through the adapter ring, but various problems may occur according to compatibility, such as electronic aperture control failure, inability to accurately measure light and inability to focus automatically. Whether it can be rotated or not is related to the structure of the camera. For example, Nikon lens can be connected to Canon body, but Nikon body cannot be connected to Canon lens.
At present, in digital SLR, Canon is most suitable for switching other bayonet lenses due to structural reasons, while Nikon still uses a small bayonet, which is the most unsuitable for switching. With the introduction of Olympus EP- 1 and Panasonic GF 1, the Micro 4/3 system has more transfer rings, which can transfer many lenses on Panasonic and Olympus cameras, including Nikon's Ai-s Canon's old FD and Leica M.