They broke it down really well on MLB network last night.
I didn't see it live, but they showed replays from different angles and slowed it down to see exactly when the ump called infield fly. They are suppose tO wait until the fly ball reaches its apex, then look to the fielder to see if he will catch it with ordinary effort. Once the ball was coming down, the umpire looked to the SS, who was calling off the LF and slowing down. As it looked like he stopped to be under the ball, the ump raised his hand making the call. Then you see the SS raise his arms having lost the ball, which as Cal Ripken pointed out, landed in a different mower line than where the SS was standing, at least 4 feet away. Harold Reynolds and Omar Vizquel said the umpire followed how they are taught to make the call. Cal disagreed and said it was never an "ordinary effort".
They also showed highlights from other games this year, where the same play happened, and the same call was made at the same distance by a LF umpire. So its not necessarily a wrong call because of the umpire or location.
I disagree with the call bc it goes against the original intent of the rule- to keep the defense from gaining an advantage by intentionally dropping the ball. The Cards weren't going to get a double play if the ball falls, so no need for the infield fly call.