 This film was the first to be photographed in the M.G.M. Camera 65  process, the second was Ben Hur (1959). Later, the process was  renamed Ultra Panavision 70. It involved using a 65mm negative with  the addition of lenses that applied a 1.25 X anamorphic squeeze.  When projected, the aspect ratio would be 2.21:1 X 1.25 = 2.76:1.  However, around 1957 cinemas were still showing Around the World In  80 Days (1956), this forced M.G.M. to release Raintree County only  on 35mm anamorphic prints, with an aspect ratio of 2.55:1. M.G.M.  used the older CinemaScope format, because it allowed for the  inclusion of 4 track magnetic audio, in contrast to the mono only  audio offered by 2.35:1 optical soundtrack prints.