If you are reading ScreenRant, you might walk away with the impression that Transformers 3 will not be in Real 3D but instead use the dreadful post-production process. Their "evidence" is rather flimsy.
...next summer you will see yet another product guilty of a post-production 3D conversion. Apparently, filming did begin in 3D, but Bay opted out when the production moved to Chicago.Recently, Avatar Director James Cameron demonstrated on G4's Attack of the Show (below) that the 3D those camera rigs are not massive anymore, looking like any other camera rig until you get close.
Considering how open the Chicago sets were to the viewing public, it’s surprising there haven’t already been more definitive answers regarding the lack of 3D camera rigs on set. ...each time I scoured the set for a 3D rig – but there were none to be found. Today’s news would explain the absence of the mammoth cameras.
Just in case you still have concerns, Michael Bay did one of his forum drive-by's and laid any doubt to rest in a post.
Who is this moron posting about what I'm shooting with??? People have no idea how hard we have worked to bring 3D filming into live action shooting. We have invented rigs and systems to place 3d cameras like no other live action movie has done before. The proof will be noticed on the final product.
Update: Added above picture of a 3D rig used in Chicago taken by MB.com admin Nelson when he commented about the ScreenRant story.