After the bundle adjustment, the
average focal length was 1743.28 pixels, with a standard
deviation of 31 pixels. The RMS of the reprojection error was
0.71 pixels. Although the camera was set at fixed focal length
(no zoom, no auto focus) during photography, the adjustment
results suggest significant focal length variation. The overall
reprojection accuracy is lower that a pixel, which suggests that
the internal geometry of the block is high.