I read somewhere that there is a nikon to ef adaptor which can stay on the camera and you can quickly change the lens without removing the adapter off the camera. I think most of the current adapters require you to remove the adapter from the camera first and then remove the adapter off the lens and then attach the adapter to the new lens you want to use and then put the adapter connected to the lens back on the camera. Does anyone know the brand of the adapter which can stay on the camera while you switch the lens? Thanks in advance for any help.