Into the Third Dimension:
Canon Brings 3-D to Video
by Ray Zone

           Canon's XLI digital video camcorder has proven itself in the field as a useful professional camera for many applications. Delivering over 500 lines of horizontal resolution with 3 interline transfer CCDs that are each 1/3" in size with 270,000 pixels, the XLI is equipped with a DV terminal that conforms to IEEE 1394 for digital transfer of video and sound, as well as regular video and audio outputs.
           To achieve a wide dynamic range, better low light and reduced vertical smears, the XLI uses a larger pixel size and a Pixel Shift process with the green CCD (carrying 60% of picture detail) shifted 1/2 pixel vertically and horizontally from the red and blue CCD signals and increasing the sampling points. The XLI is one of a few mini DV camcorders that features an interchangeable lens system with a bayonet lens mount based on Canon's EOS still camera mounting system with an adapter available to mount EF lenses.
           Canon has now introduced a new stereoscopic triple zoom lens for the XLI. With a focal length of 7.5 to 22.5mm and f numbers from f1.8 to 4.5, the 3-D unit has two separate left and right eye lenses 65mm apart which use a second common lens group for zooming and focusing. Sequential video fields display the left and right eye views alternately 60 times per second and the video signal is output by only one signal line. Both television and computer monitors with alternating field displays combined with liquid crystal shutter glasses or head-mounted displays (HMDs) are used for 3-D viewing of the stereoscopic images. Sequential field capture of the left and right-eye images is compatible with 60 hertz, 90 hertz and 120 hertz display systems.
           With a unique mirror system the optical axes of the two lenses can be "toed-in" or converged in much the same way that the human eyes converge on a closely observed subject with an adjustable dial on the top of the 3-D unit. The 3-D lens uses both auto focus and manual modes and there is an automatic convergence adjustment switch