Why are my Revit cameras
different after import and export?
The 3ds Max FBX Plug-in does not support the cropping region and optical center of Revit cameras. However, the field of view (FOV) or perspective of the Revit cameras is correct in 3ds Max. So, this does not translate precisely in 3ds Max if you modify your Revit camera by resizing and/or offsetting the cropping region (frame) of your 3D view in Revit.
This is caused by a combination of FBX not transporting the render resolution settings, and a limitation that the 3ds Max camera model does not support an optical center