Fig. 9. Scheimpflug principle: When an object plane (slit beam), objective plane (camera lens) and image plane (film plane) intersect, the result is a photograph with a deep depth of focus.47 On most Scheimpflug slit cameras, the slit beam and charged-coupled device (CCD) camera are at 45 degrees angles to each other, and the anterior eye segment (cornea to lens posterior capsule) is in focus in the resultant image.