I used the manual focus 55mm lens on a mamiya AFD body with a phase one IQ 160 back years ago and was impressed with the image quality. Excellent edge to edge sharpness and contrast with no color cast slightly stopped down. Never used the 55mm AF but understand it not to be a great performer, but have no personal experience. Wanted to try the 55mm LS lens which i hear is excellent, again no personal experience.