Two threads both dealing with Camera editing on the forum one right after the other, and still no one mentions the ability to edit CAMERA data? in the Data editor, there is a CAMERAS Data type. Select DEFAULT CAMERA and alter the fields for Distance min and distance Max to be the same number. and set INCREMENT to 0. Also, you can edit ZOOM LEVELs to make it so the camera doesnt tilt as it zooms in.
Just a note, what camera your map uses is based on the tileset being used. For example, most maps use DEFAULT CAMERA, but some use INSTALLATION camera or SPACE PLATFORM camera. Check your tileset info to set/check to see what one is used before you start altering it.