Hi, I have a lens with 3 wires...pos,neg,video...that I would like to wire into the camera...I only seem to have 2 terminals at the rear of the camera...pos,neg...and so am not sure where I need to place the video wire...I am changing the lens from a regular lens with the square type 4 pin plug...I don`t know2 if I need to maybe wire this new 3 wire lens into a 4 pin plug...can anyone help please ?