The Panzer III was several years the backbone of the german tank forces but but it failed against the T34 . The biggest weak-point of the panzer was its small turret that could not support an long 75mm cannon that would be needed to fight tanks like the T34 . So the were decided to give the PzIII an new job as support vehicle . For that it was equipped with an short 75mm cannon what was at last effective against soft targets .